BENZOPYRAN AND BENZOTHIOPYRAN DERIVATIVES AND COMPOSITIONS CONTAINING THEM

Abstract: The compounds of general formula (I), wherein R<1>, R<2>, R<3>, n, Q<1> and Q<2> are as defined in claim 1 as well as their biologically active salts. The invention also relates to fungicide, nematocide, acaricide, bactericide and insecticide compositions containing the compounds of general formula (I) as active ingredients as well as to the process for the preparation of these compounds and compositions.

Description: Benzopyran and benzothiopyran derivatives and compositions containing them The invention relates to novel benzopyran, and benzothiopyran derivatives, to their intermediates and to compositions containing the novel benzopyran and benzothiopyran derivatives. The invention also relates to the preparation of these compounds, their intermediates and of the compositions containing the novel benzopyran and benzothiopyran derivatives; further¬ more, the invention relates to the use of these composi¬ tions against πematodes, insects, worms and the like. In 1976, Bowers et al. /Science 193, 542 (1976)7 reported on the isolation of the anti-juvenile hormones of plant origin which were active against insects. After this publication, an intense research was worldwide started in order to obtain compounds surpassing the activity of the two original precocenes, i.e. precocene 1 of formula (A) and precocoπe 2 of formula (B). During the study on the action mechanism and structure-activity relations, several recognitions arose which promoted the further synthetic work (e.g. G. T. Brooks: Gen. Pharmac. _8, 221 (1977); K. Slama: Acta Eπtomol. Bohemoslov. 7_5_ > 65 (1978), etc^7. The novel benzopyran and benzothiopyran deriva¬ tives of the present invention have the general formula (I), (I) where in R and R are independently from each other hydrogen, an uπsubstituted or optionally suitably sub¬ stituted alkyl or aryl group; or R and R together may be a cycloalkyl group; R is hydrogen; an optionally protected hydroxyl group; an alkyl, alkoxy, 0-trialkyltin group; a phosphoric acid, thiophosphoric acid or phosphorous acid alkyl or aryl ester group connected through the oxygen atom; an acyloxy, acyloxyalkoxy, O-trialkylsilyl, aryloxy, alkenyloxy, alkynyloxy, cycloalkyloxy, cyclo- alkenyloxy, cycloalkylalkoxy group; an acyloxy or alkoxy group substituted by phosphoric acid, phosphαπic acid or their esters; or two adjacent R groups together may represent: an -Q-(CH 2 ) -0-group, wherein m is 1, 2, 3 or 4; or a condensed aromatic ring; or an -0-(CH 2 ) -(0) - group, wherein m is as defined above and z is 0 or 1; or an -0-P(Cl)-0-, -0-P(0C 2 H 5 )-0-, -0-P=0(0C 2 H 5 )-0- J -0-P=S(0C 2 H 5 )-0-, -0-(C=0)-0-, -0-(C=S)-0-, -Q-P=0(SC 2 H 5 )-0-, -0-P=S(SC 2 H 5 )-0- or an -0-(S=Q)-Q- group; or a halogen or a haloalkyl, nitro, amino or suitably substituted amino group; an alkoxy group substituted by an alkylamino or a dial- kylamiπo group; or a πitrile, ercapto, op¬ tionally substituted alkylthio group; an optionally ring-substituted aralkyloxy group; an acyl group; or two adjacent R groups together may also represent a -C=C-C(=Q)-0- and -C=C-C=(CH 3 ) 2 -0- group; n is 0, 1, 2, 3 or 4, and these R groups may have, independently from each other, any meaning defined for the R groups, 1 Q is oxygen, sulfur, SO or SO-; Q z is sulfur or selenium. The compounds of the general formula (I) are new; simultaneously, they contain each structural moieties of the original precoceπe 1 and precocene 2 molecules which are essential for the biological activity. However, the biotransformatioπ-sensitive double bond is preferably in a protected form. According to an other aspect of the invention, there is provided a process for the preparation of the novel compounds of the general formula (I) and salts thereof, which comprises a) reacting a compound of the general formula (II), 0 wherein Q ' R- R' R and n are as defined above, with a compound of the general formula (III), H 2 N-NH-R (III) wherein R means hydrogen, CO-alkyl, CO-aryl, CQO-alkyl, COO-aryl, CQNH 2 , CSNH 2> C0NHNH 2 , CSNHNH 2 , CNHNH 2 , CNHNHNH 2 , S0 2 -alkyl or S0 2 -aryl group, and reacting the thus-obtained compound of the general formula (IV), wherein R " R' R , R , Q and n are as defined above, with selenium dioxide in order to obtain a compound of the general formula (I), wherein 2 Q is selenium (as shown in scheme a); or b) reacting a compound of the general formula (V) wherein R , R 3 , R4 and n are as defined above, with an acid and then with selenium dioxide to obtain a compound of the general formula (I), wherein Q1 is oxygen and Q2 is selenium (as shown in scheme b) ; or c) reacting a compound of the general formula (VI) wherein R 1 , R2 , R3 , Q1, Q2 and n are as defined above, with a diazo-transfer reagent in the pre¬ sence of a base (as shown in scheme c) ; ( or d) reacting a compound of the general formula (VII) wherein R ' R Λ R , Q and n are as defined above, with acetic acid in order to obtain a compound of the general formula (I), wherein Q is oxygen (as shown in scheme d) ; VII or e) treating a compound of the general formula (VIII) wherein R ' R' R' Q1 , Q and n are as defined above and R means an alkyl, aryl, alkylamiπo or arylamiπo group, with a base (as shown in scheme e); viπ or f) reacting a compound of the general formula (IX), 3 1 2 wherein R , Q , Q and n are as defined above, with a Grignard reagent of the general formula 1 2 1 2 R gX and/or R MgX, wherein R and R are as defined above and X is halogen, or with a metal alkyl compound (as shown in scheme f) IX and, if desired, oxidizing a thus-obtained compound of the general formula (I), wherein Q is sulfur, to a compound of the general formula (I) wherein Q is an SO or S0 2 group and/or, if desired, converting a compound of the general formula (I) to the sali? thereof. The cyclizatioπ of the semicarbazoπes accord¬ ing to the process a) is known /ϊ. Lalezari, A. Shafiee: Tetrahedron Lett. 5105 (1969); I. Lalezari, A. et al.: Aπgew. Chem. &2_, 484 (1970); I. Lalezari et al.: 3 . Org. Chem. > 2836 (1971)7. However, these reactions were not extended to the preparation of systems involving more fused heterocycles. The ring systems of the com¬ pounds of the invention are new. A part of semicarbazones having the general formula (II) used as starting substances are also novel compounds. For carrying out the cyclizatioπ selenium dioxide, seleπous acid or seleπous acid derivatives (e.g. salts) or selenium oxychloride are used in the presence of C-, , aliphatic carboxylic acids or their mixtures or the mixtures of these acids with suitable selected solvents or in suspensions prepared therefrom. In the most cases, an equimolar amount of 1.1 to 1.3 equivalents of the selenium compound are used for oxidation. The reaction is usually carried out at a temperature of 0 to 120 °C, preferably at 30 to 80 °C. At the end of the mostly unidirectional re¬ action, the product is obtained by evaporation, whereby the solvent used for the reaction can be recyclized into the process . An important part of the substituted or un- substituted hydrazones, thiosemicarbazones, guanylhydra- zones, bis-carbohydrazoπes or bis-thiocarbohydrazoπes used as starting substances in process b) are also novel compounds. Thus, the invention also relates to the compounds of the general formulae (V), (X) and (XI) as well as to the preparation of these compounds. Similarly to the process a), the cycliziπg reaction is accomplished by using selenium dioxide, selenous acid or selenium oxychloride. The selenium- containing reagent is preferably used in an amount of 1.0 to 1.5 equivalents and optionally given in several portions to the compound to be cyclized. This reaction is usually carried out at 0 to 120 C, preferably between 20 °C and 80 °C. The product is separated by evaporating or pouring the reaction mixture into water optionally followed by extraction. According to process c) , a compound of the general formula (VI) is reacted with a suitably selected diazo-transfer reagent / . Regitz: Recent Synthetic Methods in Diazo Chemistry, Synthesis 1972, 3517. In the process d), a compound of the general formula (VII) is cyclized according to the first step of process b), i.e. by using an aliphatic carboxylic • acid or an inorganic acid, optionally in a miscible solvent under heating. In process e) , the cyclization is carried out by treating a compound of the general formula (VIII) with a base. The ring closure proceeds through a non- . -isolated intermediate. According to process f) of the invention, a compound of the general formula (IX) is reacted with an R 1MgX or R2MgX Grignard reagent. This method is well known in the chemistry of coumarins / . Houben: Chem. Ber. _3_7, 489 (1904)7 which has been investigated in detail /H. Decker and T. Felleπberg: Liebigs Ann. Chem. 356, 281 (1907); R. L. Shriner and A. G. Sharp.: 3 . Org. Chem. _4, 575 (1939); L. I. Smith and P. M. Rouff: 3 . Amer. Chem. Soc. 2_, 145 (1940)7 and is also being used today /H. P. Pommier et al.: Can. 3. Chem. 51, 1377 (1979); M. V. Naidu and G. S. Krishna-Rao: Proc. Iπd. Acad. Sci. 8_, 197 (1979)/. A particularly preferred but not exclusive use of the above substituents is as follows: 4-Phenyl-4H-selenadiazolo/5,4-c7/17benzopy an, 4-pheπyl-4H-seleπadiazolo/5,4-c7/I7benzothiopyran, 4-phenyl-4H-selenadiazolo/5,4-c7/I7benzothiopyran-5-oxide, 4-phenyl-4H-selenadiazolo/5,4-c7/ϊ7beπzothiopyraπ-5, 5-dioxide, 4-phenyl-4H-thiadiazolo/5,4-c7/I7benzopyran, 4-phenyl-4H-thiadiazolo/5,4-c7/I7benzothiopyran, 4-phenyl-4H-thiadiazolo/5,4-c7/I7benzothiopyran-5-oxide, 4-phenyl-4H-thiadiazolo/5,4-c7/I7benzothiopyran-5,5- -dioxide , 4H-selenadiazolo/5,4-c7/ϊ7benzopyran, 4H-selenadiazolo/5,4-c7/I7benzothiopyran, 4H-selenadiazolo/5,4-c7/I7 en zothiopyran- -oxide, 4H-selenadiazolo/5,4-c7/I7benzothiopyran-5,5-dioxide, 4,4-dimethyl-7-methoxy-4H-selenadiazolo/5,4-c7/I7benzo- pyran , 4,4-dimethyl-7-methoxy-4H-selenadiazolo/5,4-c7/I7benzo- thiopyran , 4,4-dimethyl-7-methoxy-4H-selenadiazolo/5,4-c7/I7benzo- thiopyran-5-oxide, 4,4-dimethyl-7-methoxy-4H-selenadiazolo/5,4-c7/I7benzo- thiopyran-5 , 5-dioxide , 4H-thiadiazolo/5,4-c7/I7benzopyran, 4H-thiadiazolo/5,4-c7/I7benzothiopyran, 4H-thiadiazolo/5,4-c7/I7benzothiopyran-5-oxide, 4H-thiadiazolo/5,4-c7/I7benzothiopyran-5, 5-dioxide, 4,4-dimethyl-7-methoxy-4H-thiadiazolo/5,4-c7/I7benzo- pyran , 4,4-di ethyl-7-methoxy-4H-thiadiazolo/5,4-c7/I7benzo- thiopyran , 4,4-dimethyl-7-methoxy-4H-thiadiazolo/5,4-c7/I7benzo- thiopyran-5-oxide , 4,4-dimethyl-7-methoxy-4H-thiadiazolo/5,4-c7/I7benzo- thiopyran-5, 5-dioxide, 7,8-dimethoxy-4,4-di ethyl-4H-selenadiazolo/5,4-c7/I7- benzopyran , 7,8-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5,4-c7/I7- benzothiopyran , 7 ,8-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5 > 4-c7/I7- benzothiopyran-5-oxide, 7,8-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5 ,4--c7/I7- benzothiopyraπ-5, -dioxide, 7 ,8-dimethαxy-4,4-dimethyl-4H-thiadiazolα/5,4-c7/I7benzo- pyran, 7,8-dimethoxy-4,4-dimethyl-4H-thiadiazolo/5^-cZ/I/beπzo- thiopyraπ, 7,8-dimethoxy-4,4-dimethyl-4H-thiadiazolo/5 ,4-c7/17benzo- thIopyran-5-αxide, 7,8-dimethoxy-4,4-dimethyl-4H-thiadiazolo/ ,4-c7/ϊ7benzo- thiopyraπ-5,5-dioxide, 4,4-dimethyl-7-ethoxy-8-methoxy-4H-selenadiazαlo/5,4-c7- /I7benzopyraπ, 4,4- imethyl-7-ethαxy-8-methoxy-4H-selenadiazolo/5 ,4-c7- /ϊ7beπzothio yran, 4,4-dimethyl-7-ethoxy-8-methoxy-4H-selenadiazαlo/ ,4-c7- /ϊ7benzothiα y an-5-oxide, 4,4-dimethyl-7-ethoxy-8-methoxy-4H-selenadiazolo/5 ,4-c7- /I7beπzothiopyran-5,5-dioxide, ,4-dimethyl-7-ethoxy-8-metho y-4H-thiadiazolo/5,4-c7- /I7benzopyran, 4,4-dimethyl-7-ethα y-8-methoxy-4H-thiadiazolo/5,4-c7- /I7benzothiopyran, 4,4-dimethyl-7-=thαxy-8-metho y-4H-thiadiazolo/5,4-c7- /ϊ7beπzαthiαpy an-5-oxide, 4,4-dimethyl-7-ethoxy-8-methoxy-4H-thiadiazolo/5,4-c7- /ϊ7beπzothiopyran-5,5-dioxide, 4,4-dimethyl-8-ethαxy-7-methoxy-4H-seleπadiazolo/5 ,4-c7- /I7benzopyraπ, ,4-dimethyl-8-ethoxy-7-methoxy-4H-selenadiazαlo/5,4-c7- /I7beπzothiopyran, 4,4-dimethyl-8-ethαxy-7-methαxy-4H-selenadiazolo/5 , -c7- /I7benzothiopyraπ-5-oxide, 4,4-dimethyl-8-ethoxy-7-methoxy-4H-selenadiazolo/5,4-c7- /I7beπzothIop ran-5,5-dioxide, 4,4-dimethyl-8-ethoxy-7-methoxy-4H-thiadiazolo/5,4-c7- /I7benzopyraπ , 4,4-dimethyl-8-ethoxy-7-methoxy-4H-thiadiazolo/5,4-c7/I7- benzothiopyraπ , 4,4-dime hyl-8-ethoxy-7-methoxy-4H-thiadiazolo/5,4-c7- /I7benzothiopyran-5-oxide, 4,4-dimethyl-8-ethoxy-7-methoxy-4H-thiadiazolo/5,4-c7/I7- beπzothiopyran-5,5-diαxide, 4,4-dimethyl-7-(2 ' ,2' , 2 ' -trifluoroethoxy)-4H-selena- diazolo/5 ,4-c7/ϊ7beπzopyraπ , 4,4-dimethyl-7-(2' ,2' , 2 * -trifluoroethoxy)-4H-selena- diazolo/5,4-c//ϊ/benzothiopyran, 4,4-dimethyl-7-(2',2' ,2 ' -trifluoroethoxy)-4H-seleπa- diazolo/5,4-c7/I7benzothiopyran-5-oxide, 4,4-dimethyl-7-(2 , ,2' , 2 ' -trifluoroethoxy)-4H-selena- diazolo/5,4-c7/I7benzothiopyraπ-5,5-dioxide, 7,8-diethoxy-4,4-dimethyl-4H-selenadiazolo/5,4-c7/I7- benzαpyran , 4,4-dimethyl-7-ethoxy-4H-seleπadiazolo/5,4-c7/I7beπzo- pyraπ , 4, -dimethyl-7-propoxy-4H-selenadiazolo/5,4-c7/ϊ/benzo¬ pyran , 4,4-dimethyl-7-isopropoxy-4H-selenadiazolo/5,4-c//I/- benzopyraπ, — — 7-n-butoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I/benzo- pyraπ , 7-sec.-butoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c7/I7- benzopyraπ , 4,4-dimethyl-7-isobutoxy-4H-seleπadiazolo/5,4-c//I/- benzopyran , 7-amyloxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I/benzo- pyran , 4,4-dimethyl-7-π-octyloxy-4H-selenadiazolo/5,4-c7/I7- benzopyran , 4,4-dimethyl-7-n-dodecyloxy-4H-seleπadiazolo/5,4-c7/I7- benzαpyraπ , 4,4-dimethyl-7-n-octadecyloxy-4H-selenadiazolo/5 ,4-c/- /I/benzαpyraπ, 4,4-dimethyl-7-(methoxy)methoxy-4H-seleπadiazαlo/5,4-c/- /I/benzopyran, 7-cyclopropyloxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c/- /I/beπzopyraπ, 7-cyclobutyloxy-4,4-dimethyl-4H-selenadiazolo/5,4-c/- /I/beπzopyraπ, 7-cyclopeπtylαxy-4,4-dimethyl-4H-seleπadiazolα/5, -c/- /I/beπzopyraπ, 7-cyclohexyloxy-4,4-dimethyl-4H-selenadiazαlo/5,4-c/- /I/beπzopyraπ, 7-beπzylαxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/beπ- zopyran, 7-(2-chlorobeπzyloxy)-4,4-dimethyl-4H-selenadiazolo/5,4-c/- /I/benzopyraπ, 7-benzylo y-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/- beπzothiopyraπ, 7-(3-chlorobenzyloxy)-4,4-dimethyl-4H-seleπadiazolo- /5,4-c//I/beπzopyraπ, 7-(4-chlorobeπzyloxy)-4,4-dimethyl-4H-seleπadiazolo- /5,4-c//I/benzopyraπ, 4,4-dimethyl-7-(l-πaphthylmethoxy)-4H-seleπadiazolo- /5 ,4-c//I/beπzopyran, 7-(2,3-dichlorobeπzyloxy)-4,4-dimethyl-4H-selenadiazolo- / ,4-c//I/benzopy aπ, 7-(2,4-dichlorobeπzyloxy)-4, -dimethyl-4H-seleπadiazolo- /5,4-c//I/beπzopyran, 4,4-dimethyl-7-(2-naphthylmethoxy)-4H-selenadiazolo- /5 ,4-c//I/benzopyran, 4,4-dimethyl-7-(l-tetralinyloxy)-4H-selenadiazolo/5,4-c/- /I/beπzopyraπ, 4,4-dimethyl-7-(2-tetraliπyloxy)-4H-selenadiazolo/ ,4-c7- /I/benzopyraπ, 4,4-dimethyl-7-hydroxy-4H-seIeπadiazolo/5,4-c//I/benzo¬ pyraπ, 7,8-dihydroxy-4,4-di ethyl-4H-seleπadiazolo/5,4-c7/I/- beπzopyran, 4,4-dimethyl-7-hydroxy-4H-seleπadiazolo/5,4-c//I/- beπzopyraπ, 7,8-dihydroxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/- beπzothiopyran, 7,9-dihydroxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/- beπzopyran, 6,7-dihydroxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I/- benzopyran, 4,4-dime hyl-7-hydroxy-6-methoxy-4H-selenadiazαlo/5,4-c/- /I/beπzopyraπ, 6,7-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/- benzopyran 7,9-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5 5 4-c//I/- beπzopyraπ, 7-allylαxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/- beπzopyran, 4,4-dimethyl-7-prenyloxy-4H-seleπadiazolα/5,4-c//I/- benzopyran, 7-(3-cyclopeπteπyloxy)-4,4-dimethyl-4H-selenadiazolo- /5,4-c//I/-beπzopyraπ, 7-(3-cyclohexeπyloxy)-4,4-dimethyl-4H-seleπadiazolo- /5,4-c//I/-beπzopyran, 4,4-dimethyl-7-propargyloxy-4H-seleπadiazolo/5,4-c7/I7- beπzopyraπ, 7-chloro-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I/benzo¬ pyran, 7-bromo-4,4-dimethyl-4H-seleπadiazolo/5,4-c//ϊ/beπzo- pyraπ, 4,4-dimethyl-7-trifluoromethylthio-4H-selenadiazolo- /5,4-c7/ϊ/benzopyraπ, 4,4-dimethyl-7-methylthio-4H-seleπadiazolα/5,4-c//I/- benzopyraπ, 4,4-dimethyl-7-ethylthio-4H-seleπadiazolo/5,4-c//I/beπzo- pyran, 4 I -τJifnethyl-7-(2' ,2' ,2'-trifluoroethylthio)-4H-selena- diazolo/5,4-c//I/benzαpyraπ, 7-allylthio-4,4-dimethyl-4H-selenadiazolo/5,4-c7/I/benzo¬ pyran, 4,4-dimethyl-7-propargylthio-4H-selenadiazolo/5 ,4-c7/I7- beπzopyraπ, ,4-dimethyl-7-preπylthiα-4H-selenadiazolo/5j4--c//ϊ/- benzopyraπ, 4,4-dimethyl-7-propylthio-4H-selenadiazolo/5,4-c//I/- benzopyran, 4,4-dimethyl-7-isopropylthio-4H-selenadiazolo/5,4-c//I/- benzopyraπ, 7-butylthio-4,4-dimethyl-4H-selenadiazolo/5,4-c//ϊ/- benzopyran, 4,4-dimethyl-7-isobutylthio-4H-selenadiazolo/5,4-c//I/- ben∑opyraπ, 7-sec.-butylthio-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I7- benzopyraπ, 4,4-dimethyl-7-(2-dimethylamiπoethoxy)-4H-seleπadiazolα- /5,4-c//I/beπzopyran, 4,4~dimethyl-7-(2-dimethylamiπαet ylt io)-4H-seleπa- diazolα/5,4-c//I/benzopyraπ, 7-(2-diethylamInαethylthio)-4, -dimethyl-4H-seleπa- diazolo/5,4-c//I/benzopyraπ, 7-(2-diethylaminoethoxy)- J -dime hyl- H-seleπa iazolo- / , -c//I7 eπzopy^aπ, 4,4-dimethyl-7-(2-p olidInoethoxy)-4H-seleπadiazolo- /5,4-c//ϊ7beπzopy^an, 4,4-dimeth l-7-(2-piperi iπoethoxy)-4H-selenadiazolo- /5,4-c7/I/beπzcpyran, 4,4-dimethyl-7-(2-morpholinoethoxy)-4H-seleπadiazolo- /5,4-c7/I/benzopyran, 4,4-dimethyl-7-(N-methylpiperazinoethoxy)-4H-seleπa- diazolo/5,4-c//ϊ/benzopy an, 4,4-dimethyl-7-(N-ethylpiperazinαethoxy)-4H-seleπadiazαlo- /5,4-c7/I7benzopyraπ, 7-(N-benzylpiperazinoethoxy)-4,4-dimethyl-4H-seIeπa- diazolo/5,4-c// /benzopyraπ, 4,4-dimethyl-8-methoxy-7-(2' ,2' , 2 ' -trifluoroethoxy)- -4H-selenadiazolo/5,4-c//I/beπzopyran, 4,4-dimethyl-8-me hoxy-7-propoxy-4H-seleπadiazolo/5,4-c/- /I/benzcpyran , 4,4-dimethyl-7-isopropoxy-8-methoxy-4H-seleπadiazolo- /5,4-c//I/beπzopyran, 7-π-butoxy-4,4-dimethyl-8-methoxy-4H-selenadiazαlo- /5,4-c//ϊ/benzopyraπ, 7-sec. ^ butoxy-4,4-dimethyl-8-methoxy-4H-seleπadiazolo- /5,4-c//I/beπzopyraπ, 4 ,4-dimethyl-7-isobutoxy-8-methoxy-4H-seleπadiazolo- /5,4-c//I/benzopyran, 4,4-dimethyl-7-isobutoxy-8-methoxy-4H-seleπadiazolo- / ,4-c//I/benzothiopyran . 7-amyloxy-4,4-dimethyl-8-methoxy-4H-selenadiazolo/5,4-c/- /I/beπzopyraπ , 4,4-dimethyl-8-methoxy-7-π-octyloxy-4H-selenadiazolo- /5,4-c//I/benzopyraπ, 4,4-dimethyl-7-π-dodecyloxy-8-methoxy-4H-selenadiazolo- /5,4-c//I/beπzopyraπ, 4,4-dimethyl-8-methoxy-7-n-octadecyloxy-4H-seleπadiazolo- /5,4-c//I/beπzopyraπ, 4,4-dimethyl-7-(methoxy)methoxy-4H-selenadiazolo/5,4- c//I/benzothiopyraπ, 4,4-dimethyl-8-methoxy-7-methoxyethoxy-4H-seleπadiazolo- /5,4-c//I/beπzopyraπ, 7-cyclopropyloxy-4,4-dimethyl-8-methoxy-4H-selenadiazolo- /5,4-c//I/benzopyraπ, 7-cyclopropylmethoxy-4,4-dimethyl-8-methoxy-4H-selena- diazolo/5,4-c//I/beπzopyraπ, 7-cyclobutyloxy-4,4-dimεthyl-8-methoxy-4H-seleπadiazolo- /5,4-c//I/beπzcpyraπ, 7-cyclopeπtyloxy-4,4-dimethyl-8-methoxy-4H-selenadiazolo- /5,4-c//I/benzopyraπ, 7-cyclαhexylQxy-4,4-dimethyl-8-methoxy-4H-seleπadiazαlo- /5,4-c//I/beπzopyraπ, 7-beπzyloxy-4,4-dimethyl-8-methαxy-4H-selenadiazolo- /5 ,4-c7/I7beπzopyraπ, 7-(2-chlorαbenzyloxy)- ,4-dimethyl-8-methoxy-4H-selena- diazolc/ ,4-c//I/beπzopyraπ, 7-(3-chlorobenzyloxy)- ,4~dimethyl-8-methoxy-4H-seleπa- diazolo/5,4-c7/I7benzopy an, 7-(4-chlorobeπzyloxy)-4,4-dimethyI-8-mεthoxy-4H-selena- diazolo/5 ,4-c7/I7benzopyraπ, 7-(2,3- ichlorαbeπzylαxy)-4,4-dimethyl-8-methαxy-4H- seleπadiazolα/5,4-c//I/bεnzopyraπ, 7-(2,4-dichlorobeπzyloxy)-4,4-dimethyl-8-methαxy-4H- seleπadiazolo/5,4-c//I7beπzopy aπ, 4,4-dime hyl-8-methoxy-7-(l-πaphthylmethoxy)-4H-seleπa- diazolo/5,4-c//I7benzopyraπ, 4,4-dimethyl-8-methoxy-7-(2-naphthylmethoxy)-4H-seleπa- diazolo/5,4-c//I/benzopyraπ, 4,4-dimethyl-8-methoxy-7-(l-tetraliπylo y)-4H-seleπa- diazolo/5, -c//I/benzopyraπ, 4,4-dimethyl-8-methoxy-7-(2-tetralinyloxy)-4H-selena- diazαlo/ ,4-c//I7beπzopyraπ, 4,4-dimethyl-7-hydrαxy-8-methoxy-4H-seleπadiazolo/ ,4-cZ- /I/benzopyraπ, 4,4-dimethyl-7-hydroxy-9-metho y-4H-selenadiazolo/5,4-c/- /I/beπzopyraπ, ,4-dimethyl-7-hydroxy-6-methoxy-4H-selenadiazolo/5,4-c/- /I/beπzopyraπ, 7-methoxy-4,4,6-tri ethyl-4H-selenadiazolo/5,4-c7/I7benzo- - - - pyraπ, 7-methoxy-4, ,9-trimethyl-4H-seleπadiazolo/5 , -c//I/beπzo- pyraπ, 7-ethoxy-4,4,6-trimethyl-4H-selenadiazolo/5,4-c//I/beπzo- pyran, 7-propargyloxy-4,4,6-trimethyl-4H-seIeπ diazolo/5 5 4-- //I/- benzopyraπ , 7-ethoxy-4,4,9-trimethyl-4H-selenadiazolo/5,4-c//I/benzo¬ pyran, 7-propargyloχy-4,4,9-trimethyl-4H-seleπadiazolo/5,4-c7- /I/-beπzopyraπ , 7-allyloxy-4,4-dimethyl-8-methoxy-4H-selenadiazαlo- /5,4-c//I/benzopyran, 4,4-dimethyl-8-methoxy-7-preπyloxy-4H-selenadiazolo- /5,4-c//I/benzopyran, 7-(3-cyclopeπteπyloxy)-4,4-dimethyl-8-methαxy-4H-seleπa- diazolo/5,4-c//I/benzopyran, 7-(3-cyclohexeπyloxy)-4,4-dimethyl-8-methαxy-4H-selena- diazolo/5 , -c//I/benzopyran , 4,4-dimethyl-8-methoxy-7-propargyloxy-4H-seleπadiazolo- /5,4-c//I/beπzopyraπ, 7-chloro-4,4-dimethyl-8-methoxy-4H-seleπadiazolo/5,4-c/- /I/beπzopyraπ , 7-bromo-4,4-dimethyl-8-methoxy-4H-selenadiazolo/5,4-c/- /ϊ/benzopyraπ , 4,4-dimethyl-8-methoxy-7-trifluoromethoxy-4H-selena- diazolo/5,4-c//I/beπzopyraπ, 4,4-dimethyl-8-methoxy-7-trifluoromethylthio-4H-selena- diazolo/5 , 4-c//I/beπzopyran , 4,4-dimethyl-8-methoxy-7-methylthio-4H-selenadiazolo- /5,4-c//I/beπzopyran, 4,4-dimethyl-7-ethylthio-8-me hoxy-4H-seleπadiazolo- /5,4-c//I/beπzopyran, 4,4-dimethyl-7-methylthio-8-(2' ,2' , 2 ' -trifluoroethylthio)- -4H-selenadiazolo/5,4-c7/I/benzopyran, 7-allylthio-4,4-dimethyl-8-methoxy-4H-seleπadiazolo- /5,4-c//I/beπzopyraπ, 4,4-dimethyl-8-methoxy-7-propargylthio-4H-selenadiazolo- /5 , 4-c//I/benzopyraπ , 4,4-dimethyl-8-methoxy-7-preπylthio-4H-seleπadiazolo- /5,4-c//I/benzopyraπ, 4,4-dimethyl-8-methoxy-7-propylthio-4H-selenadiazolo- /5,4-c//I/benzopyraπ, 4,4-dimethyl-7-isopropylthio-8-methoxy-4H-selenadiazolo- /5,4-c//I/beπzopyraπ, 7-butylthio- ,4-dimethyl-8-metho y-4H-selenadIazolo- /5,4-c//I/benzopy an, 4,4-dimethyl-7-isobutylthio-8-methoxy-4H-selenadiazolo- /5,4-c//I/benzopyran, 7-sec.-butylthiα-4,4-dirnethyl-8-methoxy-4H-seleπadiazolα- /5,4-c//I/beπzopyraπ, 7-(2-dieth laminαethylthio)-4,4-dimethyl-8-methoxy- -4H-selenadiazolo/5,4-c//I/benzopyran, 4,4-dimethyl-7-tributylstanπyloxy-4H-selenadiazolo/ ,4-c/- /I/beπzopyran, 4,4-dimethyl-8-methoxy-7-tributylstaπnyloxy-4H-selena- diazolo/ ,4-c//I/benzopy an, 7-diethoxyphosphoroyloxy-4,4-dimethyl-4H-seleπadiazolo- /5, -c//I/beπzopyraπ, 7-diethoxyphosphoroyloxy- ,4-dimethyl-8-methαxy-4H- seleπadiazolo/5,4-c// /beπzopyran, 4,4-dimethyl-4H-dioxolo/4,5-h/seleπadiazolo/5,4-c//I/ben¬ zopyraπ, 4,4-dimethyl-4H-/I,4/-dioxaπo/2,3-h/selenadiazolo/5 ,4-c/- /I/beπzopyran, 4,4-dimethyl-4H-/I,3/-dioxolo/4,5-g/seleπadiazolo/5,4-c/- /I/benzopyran, 4,4-dimethyl-4H-/I,4/-dioxaπo/2,3-g/seIenadiazolo/5,4-c/- /I/benzopyran, 7-metho y-5-spirocyclαpropyl-4H-seleπadiazαlo/ ,4-c/- /I7beπzopyraπ, 7,8-dimethαxy-4-spirocycloprαpyl-4H-selenadiazαlo/5,4-c7- /I/benzopyran, 8-ethoxy-7-methoxy-4-spirocyclopropyl-4H-seleπadiazolo- /5,4-c//I/benzopyraπ, 7-ethoxy-8-methoxy-4-spirocyclopropyl-4H-seleπadiazαlo- /5,4-c//I/beπzopyraπ, 7'-methoxy-spiro/cycloproane-l,4'-(4'H-selenadiazolo- /5,4-c//I/benzopyran)/ spiro/cyclopropane-1,4'-(4'H-/I,3/-dioxolo/4,5-g/selena- diazolo/5,4-c7/I/benzopyraπ)/ spiro/cyclobutane-l,4'-(4'H-/I,3/-dioxolo/4,5-g/3elena- diazolo/5,4-c//ϊ/benzopyran/, spiro/cyclopropane-l,4'-(4'H-/I,4/-dioxaπo/2,3-g/seieπa- diazolo/5,4-c//I/beπzopyraπ)7, spiro/cyclαpentane-l,4'-(4'H-/ϊ,4/-dioxaπo/2,3-h/seleπa- diazolo/5,4-c//ϊ/benzopyran)/, spiro/cyclohexan-l,4'-(4'H-/I,3/-dioxoln/4,5-g/selena- diazolo/ , -c//I/beπzopyran, spiro/cyclooctane-l,4'-(4'H-/I,3/-dioxolo/4,5-h/selena- diazolo/5,4-c//I/beπzopyran. The invention is illustrated in detail by the aid of the following non-limiting Examples. The compounds prepared were characterized also by their IR, H-NMR and mass spectra. Example 1 Preparation of 2 ,2-dimethyl-7-methoxy-4- -chromanoπe semicarbazone This compound was prepared or referred to, respectively ( . Bridge et al.: 3 . Chem. Soc. 1937 , 1530) A mixture containing 8.24 g (40 mmoles) of 2,2-dimethyl-7-methoxy-4-chromaπoπe , 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol is refluxed for 12 hours, then evaporated and the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p..: 224-226 °C (literature m.p.: 226 °C). R f : 0.12 (benzene/ethyl acetate 1:1) 0.41 (toluene /ethyl acetate/formic acid 7:3:1) 0.36 (chloroform/ethanol 9:1) Analysis: Calculated for c ι 3 H 1 7 N 3°3 ( mo l ec ular weight 263) C % = 61 , 71 ; H \ = 6 , 77 ; N % = 16 , 61 ; Found : C % = 61 , 9 ; H % = 6 , 65 ; N % = 16 , 8 ; Example 2 Preparation of 2,2-dimethyl- ,7-dimethoxy- -4-chromaπone semicarbazoπe A mixture containing 9.44 g (40 mmoles) of 2,2-dimethyI-6,7-dimethoxy-4-chromaπoπe , 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol are refluxed until the most part of the starting substance has been transformed /_as detected by thin layer chromatαgraphy (TLC_)_/. Then, the mixture is evaporated, the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 208 C which is useful for the next step without any purification. R f : 0,07 (benzene/ethyl acetate 1:1) 0,28 (toluene/ethyl acetate/ ormic acid 7:3:1) 0.35 (chlorofor /ethaπol 9:1) Analysis: Calculated for C, 4 H, g ,0. (molecular weight: 293) C h = 57.38; H % = 6.53; -N % = 14.34; Found: C % = 57.7 ; H % = 6.4 ; N % = .14.5 Example 3 Preparation of 7-methoxy-2 ,2,8-trimethyl- -4-chromanoπe semicarbazone 8.8 g (40 mmoles) of 7-methoxy-2,2,8-trimethyl- -4-chromaπoπe , 4.8 g of semicarbazide hydro¬ chloride and 5 g of ammonium acetate are refluxed In 100 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC). Then, the mixture is evaporated, the solid residue is washed with water and with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 186-188 °C, which is useful for the next step without any purification. R f = 0.14 (benzene/ethyl acetate = 1:1) 0.47 (toluene/ethyl acetate/formic acid 7:3:1) 0.37 (chloroform/ethyl acetate = 9:1) Analysis: Calculated for C, 4 H, g N--0, (molecular weight: 277) C % = 60.7 ; H % = 6.91; N % = 15.17; Found: C % = 60.9 ; H % = 6.9 ; N % = 15.3 ; Example 4 Preparation of 7-methoxy-2 ,2 ,5-trimethyl- -4-chromanoπe semicarbazone The process and working up described in Example 3 are followed, except that 8.8 g (40 mmoles) of 7-methoxy-2,2,5-trimethyl-4-chromaπoπe are used as starting material to give the title compound, m.p. : 220-222 °C. R = 0.13 (benzene/ethyl acetate = 1:1) 0.47 (toluene/ethyl acetate/formic acid = 7:3:1) 0.38 (chloroform/ethaπol = 9:1) Analysis : Calculated for C- * H,gN- j 0, (molecular weight: 277) C % = 60.7 ; H % = 6.91; N \ = 15.17; Found: C % = 60.8 ; H % = 6.9 ; N % = 15.2 ; Example 5 Preparation of 7 ,8-dimethoxy-2 ,2-dimethyl- -4-chromanone semicarbazone 9.44 g (40 mmoles) of 7 ,8-dimethoxy-2 ,2- -dimethyl-4-chromaπoπe , 4.8 g of semicarbazide hydrochloride and 4 g of ammonium formiate are refluxed in 100 ml of methanol till the transformation of the most part of the starting substance (as detected by TLC). Then, the mixture is evaporated and the solid residue is washed with water to give the title compound, m.p.: 183-185 °C, which is useful for the next step without any purification. R. = 0.10 (benzene/ethyl acetate = 1:1) 0.30 (toluene/ethyl acetate: formic acid = 7:3:1) 0.35 (chloroform:ethaπol = 9:1) Analysis: Calculated for C ] _ H i9 " N-T u OΛ (molecular weight:- 293) C = 57.38; H % = 6.53; N % = 14.34; Found: C = 57.5 : H % = 6.5 : N % = 14.5 : Example 6 Preparation of 5 ,7-dimethoxy-2,2-dimethyl- -4-chromaπoπe semicarbazone 9.44 g (40 mmoles) of 5 ,7-dimethoxy-2,2- dimethyl-4-chromanoπe are refluxed with 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of π-prαpaπol till the transformation of the most part of the starting substance (as detected by TLC). Then, " the mixture is evaporated, the solid residue is washed with water and with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 181-182 °C, which is useful for the next step without any purification. R f = 0.09 (benzene/ethyl acetate = 1:1) 0.43 (chlorofor /ethanol = 9:1) 0.39 (toluene/ethyl acetate/formic acid = 7:3:1) Analysis : Calculated for c 4 H χ9 N 3°4 (molecular weight: 293) C % = 57.38; H % = 6.53; N % = 14.34; Found: C % = 57.6 ; H % = 6.5 ; N % = 14.4 ; Example 7 Preparation of 2,2-dimethyl-7-ethoxy-4-chroma- none semicarbazone 2.2 g (10 mmoles) of 2,2-dimethyl-7-ethoxy- -4-chromanone are refluxed with 1.2 g of semi¬ carbazide hydrochloride and 1.25 g of ammonium propionate in 25 ml of isopropaπol up to the transformation of the most part of the starting substance (as detected by TLC), then the mixture is evaporated, the solid residue is washed with water and dried to give the title compound, m.p.: 183-185 °C, which is useful for cyclizatioπ or as intermediate for other reactions, too. R f = 0.13 (benzene/ethyl acetate 1:1) 0.52 (benzene/ethyl acetate/acetic acid 7:3:1) 0.42 (chloroform/ethanol 9:1) Analysis : Calculated for (molecular weight: 277) C % = 60.7 ; H % = 6.91; N % = 15.17; Found: C % = 60.9 ; H % = 6.8 ; N % = 15.3 ; Example 8 Preparation of 2,2-dimethyl-7-ethoxy-6-methoxy- -4-chromanone semicarbazone 5.0 g (20 mmoles) of 2,2-dimethyl-7-ethoxy- -6-methoxy-4-chromaπoπe are refluxed with 2.4 g of semicarbazide hydrochloride and 2.5 g of ammonium acetate in 50 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC), then evaporated and the solid residue is washed with water and with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 205-207 °C, which is useful for the next step ithout any purification. R f = 0.07 (benzene/ethyl acetate 1:1) 0.54 (benzene:ethyl acetate/glacial acetic acid 7:3:1) 0.49 (chloroform:ethanol 9:1) Analysis : Calculated for C,,-H,-,N,0. (molecular weight: 307) C = 58 . 68 ; H % = 6 . 89 ; M % = 13 . 69 ; Found : C % = 58 . 5 ; H % = 6 . 7 ; N % = 13 . 8 ; Example 9 Preparation of 2,2-dimethyl-7-isopropoχy- -6-methoxy-4-chromanone semicarbazone 2.64 g (10 mmoles) of 2,2-dimethyl-7-iso- propoxy-6-methoxy-4-chromanαπe . are refluxed with 1.2 g of semicarbazide hydrochloride and 1.25 g of ammonium acetate In 25 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC), then the mixture is evaporated, the solid residue is washed with water and with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 158-160 C, which is useful for the next step without any purification. R f = 0.12 (benzene/ethyl acetate 1:1) 0.49 (benzene/ethyl acetate/glacial acetic acid 7:3:1) 0.48 (chlorofor /ethaπol 9:1) Analysis: Calculated for C^H ^ ^N^O. (molecular weight: 321) C % = 59.86; H % = 7.22; N % = 13.09; Found: C % = 60.1 ; H % = 7.3 ; N % = 13.1 ; Example 10 Preparation of 2,2-dimethyl-7-propargyloxy- -4-chromanoπe semicarbazone 9.2 g (40 mmoles) of 2,2-dimethyl-7-propargyl- oxy-4-chromanoπe are refluxed with 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol up to the transformation of the most part of the starting substance (as detected by TLC). Then, the mixture is evaporated, the solid residue is washed with water and with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p. : 174-176 C, which is useful for the next step with¬ out any purification. R f = 0.12 (benzene/ethyl acetate 1:1) 0.54 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.44 (chloroform/ethaπol = 9:1) Analysis : Calculated for C 1 5H17N3O3 (molecular weight: 287) C % = 62.77; H % = 5.97; N % = 14.64; Found: C % = 63.1 ; H % = 6.05; N H = 14.8 ; Example 11 Preparation of 7-π-butoxy-2 , 2-dimethyl-4- -chromanoπe semicarbazone 9.92 g (40 mmoles) of 7-π-butoxy-2 , 2-dimethy1- -4-chromaπone are refluxed with 4.8 g of semi¬ carbazide hydrochloride and 5 g of ammonium acetate in 80 ml of ethanol up to the transformation of the most part of the starting substances (as detected by TLC). Then, the mixture is evaporated, the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p. : 148-151 °C, which is useful for the next step or as intermediate for other reactions without any purification. R- = 0.14 (benzene/ethyl acetate = 1:1) 0.51 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.49 (chloroform/ethaπol = 9:1) Analysis : Calculated for C-, gH ^ - j N- j O, (molecular weight: 305) C % = 63 ; H % = 7.6 ; N % = 13.78; Found: C % = 63.2 ; H % = 1. ; N % = 13.9 ; E x a mp l e 12 Preparation of 2.2-dimethyl-7-π-propoxy-4- -chromanoπe semicarbazone 2.34 g (10 mmoles) of 2 , 2-dimethyl-7-π-propαxy- -4-chromanone are refluxed with 1.2 g of semi¬ carbazide hydrochloride and 1.25 g of ammonium acetate In 25 ml of ethanol up to the transformation of the most part of the starting substance (as detected by TLC) . Then, the mixture is evaporated, the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p. : 194-196 °C, which is useful for cyclization without any purification. R f = 0.12 (benzene/ethyl acetate = 1:1) 0.52 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.45 (chlorofαrm/ethaπol = 9:1) Analysis : Calculated for C 15 H 2 ,N,0, (molecular weight: 291) C % = 61.9 ; H % = 7.27; N % = 14.44; Found: C % = 61.9 ; H % = 7.3 ; N % = 14.5 ; Example 13 Preparation of 2 ,2-dimethyl-4-chromaπone semicarbazone 1.76 g (10 mmoles) of 2 ,2-dimethyl-4-chromanone are refluxed with 1.2 g of semicarbazide hydro¬ chloride and 1.25 g of ammonium acetate in 20 ml of ethanol up to the transformation of the most part of the starting substance (as detected by TLC). Then, the mixture is evaporated, the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound mm..pp. : 1 19933-- 119955 °°CC,, wwhhiicchh iiss uusseeffuull for further trans- formations without any purification R f = 0.19 (benzene/ethyl acetate = 1:1) 0.58 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.49 (chlorαform/ethanol = 9:1) Analysis: Calculated for C, 2 H, 5 N-,0 2 (molecular weight: 233) C % = 61.85; H % = 6.49; N % = 18.03; Found: C % = 61.6 ; H % = 6.6 ; N = 18.2 ; Example 14 Preparation of 4-chromanone semicarbazone 2.5 g (16.9 mmoles) of 4-chromanone are refluxed with 1.88 g (17 mmoles) of semicarbazide hydrochloride and 2.12 g of ammonium acetate in 42 ml of ethanol t ' ill the transformation of the most part of the starting substance (as detected by TLC). Then, the mixture is evaporated and the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound in a yield of 86.7 % , m.p. : 205-208 C, which is useful for the cyclization without recrystallization or other purification. R f = 0.08 (benzene/ethyl acetate = 1:1) 0.51 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.37 (chloroform/ethanol = 9:1) Analysis : Calculated for C, ηH, , N-,0 2 (molecular weight: 205) C % - 58.58; H % = 5.41; N % = 20.5 ; Found: C % = 58.4 ; H % = 5.32; N % = 20.7 ; Example 15 Preparation of 7-allyloxy-2 , 2-dimethyl-4- -chromanone semicarbazone 18.56 g (80 mmoles) of 7-allyloxy-2 , 2-dimethyl- -4-chromaπone are refluxed ith 9.6 g of semi- carbazide hydrochloride and 10 g of ammonium acetate in 200 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC). Then, the mixture is evaporated and the solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 173-175 C, which is chromatographically uniform and useful for cycllzatiαπs with any further purification. R f = 0.08 (benzene/ethyl acetate = 1:1) 0.54 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.49 (chloroform/ethaπol = 9:1) Analysis : Calculated for C-, 5 H,gN,0, " (molecular weight: 289) C % = 62.27; H % = 6.62; N % = 14.52; Found: C % = 62.1 ; H % = 6.5 ; N % = 14.6 ; Example 16 Preparation of 7-propargyloxy-2,2,5-trimethyl- -4-chromaπoπe semicarbazone 2.44 g (10 mmoles) of 7-propargyloxy-2,2,5- -trimethyl-4-chromanone are refluxed with 1.2 g of semicarbazide hydrochloride and 1.2 g of ammonium acetate in 25 ml of ethanol till the transformation of the most part of the starting substance (as detected the mixture _is by TLC), then/evaporarteα. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 195-198 °C, which is useful for further transforma¬ tions without any purification. R = 0.11 (benzene/ethyl acetate = 1:1) 0.51 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) Q.44 (chloroform/ethaπol = 9:1) A π a l v s i s : Calculated for C, 6 H,gN,0- j (molecular weight: 301) C % = 63.84; H % = 6.36; N % = 13.96; Found 64.1 6.5 14.1 Example 17 Preparation of 7-propargyloxy-2 , 2 , 8-trimethyl- -4-chromanone semicarbazone 9.77 g (40 mmoles) of 7-propargyloxy-2 , 2 , 8- -trimethyl-4-chromanoπe are refluxed with 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC) and evaporated. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p. : 193-196 °C, which is useful as intermediate for further reactions without any purification. R f = 0.15 (benzene/ethyl acetate = 1:1) 0.56 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.46 (chloroform/ethanol = 9:1) Analysis : Calculated for c ιg H N 3°3 (molecular weight: 301) C \ = 63.84; H % = 6.36; N % = 13.96; Found: C % = 64 ; H % = 6.5 ; N % = 13.9 ; Example 18 Preparation of 2 , 2-dirnethyl-6 ,7-ethylenedioxy- -4-chrαmaπoπe semicarbazone 2.34 g (10 mmoles) of 2 , 2-dimethyl-6 , 7-ethylene- dioxy-4-chromanone . are refluxed with 1.2 g of semicarbazide hydrochloride and 1.2 g of ammonium acetate in 20 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC), then evaporated. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate to give the title compound, m.p.: 203-206 C, which is useful for cyclizatioπ reactions without any purification. R f = 0.12 (benzene/ethyl acetate = 1:1) 0.53 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.44 (chlorαform/ethaπol = 1:1) Analysis: Calculated for ^ I Λ ^ I I ^ ^ (molecular weight: 291 C % = 57 . 78 ; H % = 5 . 89 ; N % = 14 . 44 found: C % = 57 . 6 ; H % = 5 . 9 ; N % = 14 . 3 Example 19 Preparation of 2,2-dimethyl-6,7-methyleπedioxy- -4-chromanone semicarbazone 8.8 g (40 mmoles) of 2,2-dimethyl-6,7-methylene- dioxy-4-chromaπoπe are refluxed with 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC), then evaporated. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 188-191 °C, which is useful for further reactions without any purification. R. = 0.08 (benzene/ethyl acetate = 1:1) 0.70 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.41 (chloroform/ethaπol = 9:1) Analysis: Calculated for C^H^N^O^ (molecular weight: 277) C % = 56.36; H % = 5.46; N % = 15.17; found: C % = 56.5 ; H % = 5.6 ; N % = 15.3 . Ex a mp le 20 Preparation of 2 ,2-dimethyl-7 , 8-ethylenedioxy- -4-chromanone semicarbazone 2.34 g (10 mmoles) of 2 , 2-dimethyl-7 , 8-ethyleπe dioxy-4-chromanoπ are refluxed with 1.2 g of semicarbazide hydrochloride and 1.25 g of ammonium acetate in 25 ml of isopropanol till the transformation of the most part of the starting substance (as detected by TLC), then evaporated. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p. : 236-238 °C, which can be used without any purifica¬ tion . R^ = 0.07 (benzene/ethyl acetate = 1:1) 0.50 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.43 (chloroform/ethaπol = 9:1) Analysis : Calculated for C, H,-,N-,0 (molecular weight: 291) C = 57.78; H % =.5.89; N % = 14.44; found: C % = 57.6 ; H % = 5.7 ; N % = 14.4 . Example 21 Preparation of 2 ,2-dimethyl-7 , 8-methylenedioxy- -4-chromanone semicarbazone 2.2 g (10 mmoles) of 2 , 2-dimethyl-7 , 8-methyleπe- dioxy-4-chromanoπe are refluxed with 1.2 g of semicarbazide hydrochloride and 1.25 g of ammonium acetate in 25 ml of ethanol till the transformation of the most part of the starting substance (as detected by TLC), then evaporated. The solid residue is washed ith water and then with an 1:1 mixture of benzene and ethyl acetate an dried to give the title compound, m.p. : 194-197 C, which is chromatographically uniform and useful for further transformations without any purification . f = 0.07 (benzene/ethyl acetate = 1:1) 0.52 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.61 (chlorof rm/ethanol = 9:1) Analysis : Calculated for c H χ5 N 3°4 (molecular weight: 277) C % = 56.36; H % = 5.46; N % = 15.17; found: C % = 56.2 ; H % = 5.4 ; N % = 15.3 . IR (KBr): 3490, 3150, 3050, 2980, 1679, 1643, 1458, 1408, 1357, 1059 cm "1 . MS (El, 70 eV): 277 (M + , 70 %) , 219 (91 %) , 189 (38 %), 161 (16 %), 77 (21 %), 36 (100 %). 1 H-NMR (200 MHz, 0MS0-d ≤ , cT m as related to DSS): 1.25 (s, 6H, gem. dimethyl); 2.8 (s, C-3 CH 2 , 2H); 6.0 (s, 2H, -0-CH 2 ~0-) ; 6.5 (d, 1H, aromatic); 7.3 (2H, NH 2 ); 7.8 (d, 1H, aromatic); 9.3 (s, 1H, NH) . 13 C-NMR (50.3 (MHz, DMS0-d '6., C?~ppm): 26.3, 35.2, 76.2. 101.8, 115.7, 118 139, 149, 157. Example 22 Preparation of 2-pheπyl-4-chromanone semicar¬ bazone A solution of 60 g of sodium acetate and 11.4 g (0.1 mole) of semicarbazide hydrochloride in 150 ml of water is added to a solution of 22.4 g (0.1 mole) of 4-flavaπone in 500 ml of ethanol, then the mixture Is refluxed till the complete transformation of the starting substance and then evaporated. The residue is diluted with water, the product is filtered, washed with water and dried to give the title compound in a yield of 19.5 g + 5.1 g (i.e. in a total yield of 87.2 %) which may be recrystallized from ethanol, however, it Is useful for cyclization without purifica- tioπ, m.p. : 192-194 °C. An a l y s i s : Calculated for c 16 H 15 N-,0 2 (molecular weight: 281) C % = 68.3 ; H % = 5.37; N % = 1 . * 94; found: C % = 68.3 ; H = 5.5 ; N % = 15.0 . Example 23 Preparation of 2,2-dimethyl-6 ,7-dipropargyl- oxy-4-chromanone semicarbazone 11.36 g (40 mmoles) of 2,2-dimethyl-6,7-di- propargyloxy-4-chromanoπe are refluxed with 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol for 12 hours, then evaporated. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 190-193 °C. R- = 0.16 (benzene/ethyl acetate = 1:1) 0.46 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.4 (chlorofor /ethanol = 9:1) Analysis: Calculated for C, g H, N-rO * (molecular weight: 341) C % = 63.39; H % = 5.61; N % = 12.32; found: C % = 63 ; H % = 5.7 ; N % = 12.2 . Example 24 Preparation of 2,2-dimethyl-6-ethoxy-7-methoxy- -4-chromanon semicarbazone 10 g (40 mmoles) of 2,2-dimethyl-6-ethoxy- -7-methoxy-4-chromaπoπe are refluxed with 4.8 g of semicarbazide hydrochloride and 5 g of ammonium acetate in 100 ml of ethanol for 12 hours, then evaporated. The solid residue is washed with water and then with an 1:1 mixture of benzene and ethyl acetate and dried to give the title compound, m.p.: 185-188 °C. R f = 0.12 (benzene/ethyl acetate = 1:1) 0.51 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.35 (chloroform/ethanol = 9:1) Ana lysi s : Calculated for C^H^N^O^ (molecular weight: 307) C % = 58.68; H % = 6.9 ; N % = 13.69: found: C % = 57 ; H % = 6.0 ; N % = 13.75. Example 25 Preparation of 4-pheπyl-4H-selenadiazolo- /5,4-c//I/beπzopyran 14.06 g (0.05 mole) of 2-pheπyl-4-chromanoπe semicarbazone (prepared as described in Example 22) is heated in the solution of 5.55 g (0.05 mole) of selenium dioxide in 50 ml of glacial acetic acid at 80 °C for 3 hours under stirring. Then, the mixture Is diluted with water, extracted with chloroform and the combined organic phase is dried and evaporated under vacuum. When necessary, the thus-obtained title product Is recrystallized (e.g. from methanol, ethanol, petroleum ether or ethyl acetate), m.p.: 168-171 C. R f = 0.22 (benzene/ethyl acetate = 1:1) 0.60 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.52 (chloroform/ethaπol = 9:1) Analysis: Calculated for C-, ,-H " N 2 0Ss (molecular weight: 313) C % = 57.51; H % = 3.22; N % = 8.95 ; found: C % = 57.43; H = 3.30; N % = 9.12 . Example 26 Preparation of 4,4-dimethyl-7-methoxy-4H-selena- diazolo/5 ,4-c//I/benzopyran 5.1 g (20 mmoles) of 2,2-dimethyl-7-methoxy- -4-chromaπone semicarbazone and 2.22 g (20 mmoles) of selenium dioxide are heated in 50 ml of glacial acetic acid under stirring until the gas evolution ceases, then evaporated. The residue is washed with water. On rubbing, the product solidifies, m.p..- 57- -60 °C. R = 0.68 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = 7:3:1) 0.78 (chloroform/ethanol = 9:1) Analysis : Calculated for C, 2 H, 2 N,-0 2 Se (molecular weight: 295) C % = 48.85 H % = 4.10; N 9.49 found : C % = 49.0 ; H % = 4.1 ; N % 9.6 • Example 27 Preparation of 7 ,8-dimethoxy- -4,4-dime hyl-4H-selenadiazolo/5 ,4-c//I/benzo- pyraπ 5.87 g (20 mmoles) of 6 ,7-dimethoxy-2 ,2-di- methyl-4-chromaπone semicarbazone and 2.5 g (22 mmoles) of selenium dioxide are heated in 50 ml of glacial acetic acid under stirring until the gas evolution ceases. The mixture is evaporated, the oily residue is dissolved in chloroform, washed with sodium hydrogen carbonate solution and then with water, dried, filtered through celite and then evaporated to give the title compound, m.p. : 98-100 °C. R f = 0.62 (benzene/ethyl acetate = 1:1) 0.69 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethanol = 9:1) Analysis: Calculated for (molecular weight: 325) C % = 48.04; H % = 4.34; N % = 8.62 ; found: C \ = 48.3 ; H % = 4.4 ; N % = 8.6 . Example 28 Preparation of 4 , 4-dimethyl-7-ethoxy-8-methoxy- -4H-selenadiazolo/5 , -c//ϊ/benzopyran 1.6 g (5 mmoles) of 2 , 2-dimethyl-6-methoxy- -7-ethoxy-4-chromaπ ne are heated in 12 ml of formic acid under stirring, whilst 0.6 g (about 5.4 mmoles) of selenium dioxide are added in several portions. After cessation of the gas evolution, the mixture is evaporated, the residue is dissolved in an 1:1 mixture of benzene and ethyl acetate and filtered through a silicagel layer. After evaporation, the residue solidi¬ fies (eventually rubbing is necessary), m.p.: 84-87 °C. R f = 0.68 (benzene/ethyl acetate = 1:1) 0.68 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethaπol = 9:1) Analysis: Calculated for c i4 H χ Evl 2 0 Se (molecular weight: 339) C % = 49.6 ; H % = 4.76; N % = 8.26 ; found: C % = 49.4 ; H % = 4.9 ; N % = 8.3 . Example 29 Preparation of 6 ,7-dimethoxy-4,4-dimethyl- -4H-selenadiazolo/5,4-c//I7benzopyran 2.93 g (10 mmoles) of 7,8-dimethαxy-2,2-di- methyl-4-chromanoπe semicarbazone are heated in 25 ml of propioπic acid under stirring, whilst 1.33 g (12 mmoles) of selenium dioxide are portioπwise added. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated and the product is recrystallized to give the title compound, m.p.: 225-227 °C. R- = 0.66 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethanol = 9:1) Analysis: Calculated for C,-τH, , N„ ϋ^ Se (molecular weight: 325) C % =48.04; H % = 4.34; N % = 8.62 ; found: C % = 48.2 ; H % = 4.3 ; N % = 8.8 . E x amp le 30 Preparation of 7-methoxy- .4 ,9-trimethy1- -4H-selenadiazolo/ , 4-c//I7benzopyran To a heated solution of 27.7 g (100 mmoles) of 7-methoχy-2,2,5-trimeth l-4-chromanone semicarbazone in 250 ml of glacial acetic acid, 13.3 g (12 mmoles) of selenium dioxide are portionwise added under stirring and reacted until cessation of the gas evolution. The completion of the cyclizatioπ is controlled by TLC. The mixture is evaporated and the oily residue is crys¬ tallized by rubbing to give the title compound, m.p. : 90-93 °C. R f = 0.72 (benzene/ethyl acetate = 1:1) 0.75 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.75 (chloroform/ethanol = 9:1) Analysis : Calculated for C, -,H, . N 2 0 2 Se (molecular weight: 309) C % = 50.53; H % = 4.57; N % = 9.07 ; found: C % = 50.7 ; H % = 4.5 ; N % = 9.2 . Example 31 Preparation of 7-methoxy-4 ,4 , 6-trimethyl- -4H-seleπadiazolo/5 , 4-c//I/beπzopyran 2.77 g (10 mmolesj of 7-methoxy-2 ,2 , 8-trimethyl- -4-chromanoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and control by TLC, the mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for the cyclizatioπ.) The oily residue is crystallized to give the title compound in a yield of 85.8 % , m.p. : 50-53 °C. R = 0.73 (benzene/ethyl acetate = 1:1) 0.77 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethanol = 9:1) Analysis: Calculated for C . ^ H. -N O Se (molecular weight: 309). J LA L i- C % = 50.53; H 4.57 N = 9.07 found: C % = 50.3 ; H 4.5 N = 9.2 Example 32 Preparation of 7-propargyloxy- -4,4,9-t imathyI-4H-seleπadiazolo/5,4-c//I/- beπzopyran 3.01 g (10 mmoles) of 7-propargyloxy-2,2,5- -trimethyl-4-chromaπoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirr¬ ing. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used in the cycliza¬ tion reaction). The oily residue is crystallized to give the title compound, m.p.: 63-65 C. R f = 0.69 (benzene/ethyl acetate = 1:1) 0.72 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.76 (chloroform/ethaπol = 9:1) Analysis: Calculated for C-, ,-H, ^t^O ^ Se (molecular weight: 333) C % = 54.1 ; H % = 4.24; N % = 8.41 ; found: C % = 54 ; H % = 4.4 ; N % = 8.3 . ' Example 33 Preparation of 7,9-dimethoxy-4,4-dimethyl- -4H-seleπadiazolo/5 ,4-c//I7benzopyran 29.3 g (0.1 mole) of 5 ,7-dimethoxy-2,2-dimethyl- -4-chromanαπe semicarbazone dissolved in 250 ml of glacial acetic acid are reacted with 14.43 g of selenium dioxide added in several portions while heating and stirring. After cessation of the gas evolution, the mixture is filtered, evaporated and the residue is washed with water to give the title compound, m.p.: m . p . : 113 - 114 °C . R f = 0.67 (benzene/ethyl acetate = 1:1) 0.66 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethaπol = 9:1) Analysis : Calculated for C-, ,H. 4 N„0-,Se (molecular weight: 325) C % = 48.04; H % = 4.34; N % = 8.62 ; found: C % = 48.0 ; H % = .3 ; N % = 8.7 . Example 34 Preparation of 4 , 4-dimethyl-7 , 8-dipropargyl- oxy-4H-selenadiazolo/5,4-c///benzopyran 3.41 g (10 mmoles) of 2 , 2-dimethyl-6 , 7-di- propargyloxy-4-chromaπone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p. : 78-81 °C. R f = 0.71 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethaπol = 9:1) Analysis : Calculated for C-, 7 H- . N 0.,Se (molecular weight: 373) C % = 54.74; H % = 3.78; N % = 7.51 ; found: C % = 54.4 ; H % = 4.0 ; N % = 7.4 . Example 35 Preparation of 7-propargyloxy-4 , , 6-trimethyl- -4H-selenadiazolo/ ,4-c//I/benzopyran 3.01 g (10 mmoles) of 7-propargyloxy-2 ,2 , 8- -trimethyl-4-chromanoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 113-115 C. R f = 0.74 (benzene/ethyl acetate = 1:1) 0.74 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethanol = 9:1) Analysis: Calculated for C, ,-H..N 2 0 Se (molecular weight: 333) C % = 54.1 ; H % = 4.24; N % = 8.41 ; found: C % = 54.21; H % = 4.04; N % = 8.5 . Example 36 Preparation of 4,4-dimethyl-8-ethoxy-7-methoxy- -4H-selenadiazolo/5 ,4-c7/I/beπzopyran 3.07 g (10 mmoles) of 2,2-dimethyl-6-ethoxy- -7-methoxy-4-chromanone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 70-72 °C. R~ = 0.69 (benzene/ethyl acetate = 1:1) 0.67 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethanol = 9:1) Analysis: Calculated for C, .H, ,N 2 0,Se (molecular weight: 339) C % = 49.6 ; H % = 4.76; N % = 8.26 found: C % = 48.8 : H % = 4.6 ; N % = 8.1 E x amp le 37 Preparation of 4 ,4-dimethyl-selenadiazolo- /5,4-c/-dioxano/2,3-f/-4H-/I/benzopyran 2.91 g (10 mmoles) of 2,2-dimethyl-7 ,8-dioxano- -4-chromanone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cycli¬ zation.) The oily residue is crystallized to give the title compound, m.p.: 127-131 °C. R f = 0,6 (benzene/ethyl acetate = 1:1) 0,73 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0,55 (chloroform/ethaπol = 9:1) Analysis: Calculated for C,-τH, 2 N 2 0-,Se (molecular weight: 323) C % = 48.34; H % = 3.75; N = 8.67 found: = 48.0 H = 4.1 N = 8.7 Example 38 Preparation of 4,4-dimethylselenadiazolo- /5,4-c/-dioxolo/4,5-f/-4H-/I/beπzopyran 2.77 g (10 mmoles) of 2,2-dimethyl-7,8-methy- leπedioxy-4-chromaπone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 151-154 °C. R. = 0.64 (benzene/ethyl acetate = 1:1) 0.7 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.73 (chloroform/ethanol = 9:1) Ana lysis : Calculated for C, 2 H N 0 Se (molecular weight: 309) C % = 46.64; H % = 3.26; N % = 9.07 ; found: C % = 46.4 ; H % = 3.0 ; N = 9.1 . Example 39 Preparation of 4,4-dimethylselenadiazolo- /5 ,4-c/-dioxano/2, -e/-4H-/I/beπzopyran 2.91 g (10 mmoles) of 2,2-dimethyl-6,7-dioxano- -4-chromaπone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cycli¬ zation.) The oily residue is crystallized to give the title compound, m.p.: 102-106 °C. R- = 0.64 (benzene/ethyl acetate = 1:1) 0.76 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.64 (chloroform/ethanol = 9:1) Analysis: Calculated for C-, -,H. 2 N 2 0-,Se (molecular weight: 323) C % = 48.34; H % = 3.75; N % = 8.67 ; found: C % = 48.4 ; H % = 4.1 ; N % = 8.3 . Example 40 Preparation of 4,4-dimethylselenadiazolo- /5,4-c/-dioxolo/4 ,5-e/-4H-/I/benzopyraπ 2.77 g (10 mmoles) of 2,2-dimethyl-6,7-methy- lenedioxy-4-chrαmanoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 87-104 °C. R f = 0.83 (benzene/ethyl acetate = 1:1) 0.75 (benzene/ethyl acetate/glacial acetic acid = 7:3:1) 0.75 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, H, n N 0-,Se (molecular weight: 309) C % = 46.64; H % = 3.26; N % = 9.07 ; found: C % = 46.4 ; H % = 3.0 ; N % = 9.17 . Example 41 Preparation of 6 ,7-dimethoxy-2 ,2-dimethyl- -4-chromanone acetylhydrazoπe 2.36 g (10 mmoles) of 6 ,7-dimethoxy-2 ,2-di- methyl-4-chromaπoπe and 0.8 g (11 mmoles) of acetyl- hydrazine are refluxed in 25 ml of ethanol till the complete transformation. Then, the solvent is evapor¬ ated and the residue is recrystallized to give the title compound, m.p.: 98-102 °C. R ~ = 0.54 (benzene/ethyl acetate = 1:1) 0.52 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.48 (chloroform/ethanol = 9:1) Analysis: Calculated for (molecular weight: 292) C % = 61.64; H % = 6.85; N % = 9.59 ; found: C % = 61.4 : H % = 6.8 ; N % = 9.4 . Example 42 Preparation of 7 ,9-dimethoxy-4 ,4-dimethyl- -4H-selenadiazolo/5 ,4-c//I/benzopyran 33.6 g (0.1 mole) of 5 ,7-dimethoxy-2,2-dimethyl- -4-chromanone isopropyloxycarbonylhydrazone in 300 l of glacial acetic acid are cyclized by portionwise adding 12.2 g (0.11 mole) of seleniumdioxide while mildly heating and stirring. The completion of the reaction is controlled by TLC. Then, the solvent is e.vaporated under vacuum and, if necessary, the residue is purified by recrystallizatioπ to give the title compound, m.p.: 113-114 C. R f = 0.67 (benzene/ethyl acetate = 1:1) 0.66 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethanol = 9:1) Analysis: Calculated for C, - j H, 4 N 2 0-,Se (molecular weight: 325) C % = 48.04; H % = 4.34; N % = 8.62 ; found: C % = 48.0 ; H % = 4.4 ; N % = 8.7 . Example 43 Preparation of 7,8-dimehoxy-4,4-dimethyI- -4H-seleπadiazolo/5,4-cZ/I/benzopyran To 3.09 g (10 mmoles) of ,7-dimethoxy-2,2- -dimethyl-4-chromaπone thiosemicarbazoπe dissolved in 25 ml of tetrahydrofuran, 10 ml (13 mmoles) of sele¬ πous acid solution are dropwise added while stirring. The stirring is continued till the complete transforma¬ tion (as detected by TLC). Then, the mixture is partial¬ ly evaporated and water and chloroform are added to the residue. The organic phase is separated, washed with water, dried and evaporated to give the title compound, m.p.: 98-100 C. R f = 0.62 (benzene/ethyl acetate = 1:1) 0.69 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethaπol = 9:1) Analysis: Calculated for C,-,H, ^N^O- ^ Se (molecular weight: 325) C % = 48.04; H % = 4.34; N % = 8.62 ; found: C = 48.2 ; H % = 4.3 ; N % = 8.7 . E x a mp le 44 Preparation ' of 7-methoxy-4,4,9-trimethyl- -4H-seleπadiazolo/ , 4-c//I/benzopyran 2.93 g (10 mmoles) of 7-methoxy-2 , 2 , 5-trimethyl- -2H-4-chromaπoπe thiosemicarbazone are suspended in 15 ml of dioxaπe and cyclized by adding 1 ml (13 mmoles) of seleπous acid under stirring. The end of the reac¬ tion is observed on the cessation of the gas evolution and by TLC control. The product is obtained by extrac- tion or evaporation. In the most cases, the oily residue contains only the target compound and crystallizes readily to give the title compound, m.p. : 90 - 92.5 °C. R f = 0.72 (benzene/ethyl acetate = 1:1) 0.75 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.75 (chloroform/ethanol = 9:1) Analysis : Calculated for C-, - j H, ^N ^ O^Se (molecular weight: 309) C % = 50.53 ; H % = 4.57; N % = 9.07 ; found 50.7 H 4.6 N 9.0 Example 45 Preparation of 4 ,4-dimethyl-7-ethoxy-4H- -selenadiazolo/5 , 4-c//I/benzopyraπ 1.44 g (13 mmoles) of selenium dioxide are portionwise added to the solution of 3.06 g (10 mmoles) of 2 , 2-dimethyl-7-ethoxy-4-chromaπoπe N-ethoxycarboπyl- hydrazoπe in 25 ml of glacial acetic acid while heating and stirring. After completion of the reaction, the mixture is filtered and the solution is evaporated under vacuum for recovering the solvent. The oily residue becomes crystalline; it is uniform according to TLC and can directly be used in this form or as intermediate for further transformations without any purification, m.p 104-106 U C. R = 0.75 (benzene/ethyl acetate = 1:1) 0.72 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.72 (chloroform/ethanol = 9:1) Analysis: Calculated for C-, (molecular weight: 309) C % = 50.53; H % = 4.57; N % = 9.07 ; found: C % = 50.4 ; H % = 4.5 ; N % = 9.2 . Example 46 Preparation of 4-phenyl-4H-selenadiazolo- /5 ,4-c//I/beπzopyraπ 1.33 g (12 mmoles) of selenium dioxide are portionwise added to the solution of 2.97 g (10 mmoles) of 2-pheπyl-4-chromanone thiosemicarbazone in 25 ml of glacial acetic acid at 60 °C under stirring. The stirring is continued until the cessation of gas evolu¬ tion and complete transformation of the starting mate¬ rial (as detected by TLC). Then, the mixture is evapor- ated and the recoved glacial acetic acid is used for the next cyclization. The residue is dissolved in chloro¬ form, washed with alkali, dried and evaporated. If necessary, the residue is recrystallized to give the title compound, m.p.: 168-171 C. R f = 0.22 (benzene/ethyl acetate = 1:1) 0.60 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.52 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, ,-H, Q N 2 0Se (molecular weight: 313) c % = 57.51? H % = 3.225 N % = 8 . 95 ; found : C % = 57.305 H % = 3.3 5 N % = 9.10 • E x a mple 47 Preparation of 7-methoxy-4 ,4 ,6-trimethyl-4H- -selenadiazolo/5,4-c//I/benzopyran 2.92 g (10 mmoles) of 7-methoxy-2 ,2 ,8-trimethy1- -4-chromaπoπe N-methoxycarbonylhydrazαπe in the mixture of 30 ml of dioxaπe and 10 ml of water are cyclized by adding 5 ml (11 mmoles) of seleπous acid under stirr¬ ing. The completion of the reaction is followed by TLC. Then, the reaction mixture is filtered, evaporated and recrystallized from benzene, if necessary, to give the title compound, m.p.: 58-60 C. The thus-obtained product can directly be used in this form or as inter¬ mediate . R f = 0.68 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.78 (chloroform/ethanol = 9:1) Analysis : Calculated for Cχ3H N2θ2Se (molecular weight: 309) C % = 48.85; H % = 4.10; % = 9.49 ; found: C % = 49.0 ; H % = 4.2 ; N % = 9.6 . Example 48 Preparation of 4 ,4-dimethyl-7-methoxy-4H- -selenadiazolo/5 ,4-c7/1/benzopyran 2.78 g (10 mmoles) of 2 ,2-dimethyl-7-methoxy- -4-chromanoπe N-methoxycarboπylhydrazone are stirred with 1.33 g (12 mmoles) of selenium dioxide in 25 ml of glacial acetic acid under mildly stirring till the cessation of the gas evolution. The stirring is conti¬ nued up to completion of the reaction (as detected by TLC), then filtered and evaporated to give the title compound, m.p.: 58-60 C, which can directly be used in this form or as intermediate R f = 0.68 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.78 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, 2 H, 2 N 2 0 2 Se (molecular weight: 295) C % = 48.85; H % = 4.10; N % = 9.49 ; found: C % = 48.9 ; H % = 4.2 ; N % = 9.6 . Example 49 Preparation of 7-allyloxy-4,4-dimethyl-4H- -selenadiazolo/5,4-c//I/benzopyran 11.52 g (40 mmoles) of 7-allyloxy-2,2-dimethyl- -4-chromaπoπe acetylhydrazone in 100 ml of propioπic acid are cyclized by portionwise adding 5.0 g (45 mmoles) of selenium dioxide. After cessation of the gas evolu¬ tion and completion of the reaction (as detected by TLC), the mixture is evaporated, whereby 90 to 95 % of the propioπic acid are recovered. The workiπg-up may be carried out in such a way that the thus-obtained product is dissolved in ethyl acetate, the organic phase is washed with alkali, dried and evaporated to give the title compound in a yield of 88 %, m.p.: 63- -65 C after recrystallization from a mixture of benzene and ethyl acetate). R f = 0.69 (benzene/ethyl acetate = 1:1) 0.78 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.70 (chloroform/ethanol = 9:1) Analysis: Calculated for C, / ,H-. 4 N 2 0 2 Se (molecular weight: 321) C % = 52.33; H % = 4.36; N % = 8.72 ; found: C % = 52.2 ; H % = 4.2 ; N % = 8.8 . E xa mp le 50 Preparation of 4 ,4-dimethyl-7-proparqyloχy- -4H-selenadiazolo/5 , 4-c//I/beπzopyran 39.8 g (0.1 mole) of 2 , 2-dimethyl-7-propargy1- oxy-2H-4-chromaπone tosylhydrazone are suspended in 150 ml of dioxaπe and 10 ml of water and cyclized by adding 13.32 g (0.12 mole) of selenium dioxide while stirring. The completion of the reaction is controlled by TLC. Then, the reaction mixture is evaporated and the oily residue is crystallized to give the title compound, m.p. : 83-85 C. R- = 0.7 (benzene/ethyl acetate = 1:1) 0.73 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.66 (chloroform/ethanol = 9:1) Analysis : Calculated for C, H, 2 N 2 0 2 Se (molecular weight: 319) C % = 52.71; H h = 3.79; N % = 8.78 ; found: C % = 52.4- ; H % = 3.7 ; N = 8.9 . Example 51 Preparation of 6 ,7-dimethoxy-4 , 4-dimethyl-4H- -selenadiazolo/5 ,4-c//I/benzopyran 2.5 g of 7 , 8-dimethoxy-2 , 2-dimethyl-4-chroma- none hydrazone are cyclized in 25 ml of tetrahydrofuran by portionwise adding 2.0 g (12 mmoles) of selenium oxychloride while stirring. After the complete transforma¬ tion of the starting material (as detected by TLC), the reaction mixture is heated under stirring for one additional hour, then evaporated, if necessary, and the residue is recrystallized from a suitable solvent to give the title compound. f = 0.66 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethanol = 9:1) Aπa lys is : Calculated for C 1 H 14 2 0 Se (molecular weight: 325) C % = 48.04; H % = 4.34; N % = 8.62 ; found: C % = 48.2 ; H % = 4.3 ; N % = 8.7 . Example 52 Preparation of 4,4-dimethyl-7-ethoxy-8- -methoxy-4H-seleπadiazolo/5,4-c//I/benzopyraπ 34.2 g (0.1 mole) of 2,2-dimethyl-6-methoxy- -7-ethoxy-4-chromaπoπe N-methaπesulfoπylhydrazone are cyclized in 350 ml of formic acid by portionwise adding 14.43 g (0.13 mole) of selenium dioxide while stirring. After TLC control, the reaction mixture Is diluted with water, neutralized and the product is separated by extraction into chloroform. After evaporation, the title product becomes crystalline, m.p.: 85-87 C, and can be used either directly in this form or as intermediate. R f = 0.68 (benzene/ethyl acetate = 1:1) 0.68 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, H- ,N 2 0,Se (molecular weight: 339) C % = 49.6 ; H % = 4.76; N % = 8.26 ; found C % = 49.4 H = 4.8 = 8.4 Example 53 Preparation of 4,4-dimethyl-7,8-dipropargyl- oxy-4H-selenadiazolo/5,4-c//I/benzopyran 3.41 g (10 mmoles) of 2,2-dimethyl-6,7-di- propargyloxy-4-chromanone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclizatioπ.) The oily residue is crystallized to give the title compound, m.p.: 78-81 C. R f = 0.71 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethanol = 9:1) Analysis: Calculated for C, 7 H, ^t^O- j Se (molecular weight: 373) C % = 54.74; H % = 3.78; N % = 7.51 ; found: C % = 54.4 ; H % = 4.0- ; N = 7.4 . Example 54 Preparation of ,4-dimethyl-8-ethoxy-7-methoxy- -4H-selenadiazolo/5 ,4-c//ϊ/benzopyran 3.07 g (10 mmoles) of 2,2-dimethyl-6-ethoxy- -7-methoxy-4- -chromaπoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 " mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 70-72 °C. R f = 0.69 (benzene/ethyl acetate = 1:1) 0.67 (benzene/ethyl acetate/glacial acetic acid = 0.74 = 7:3:1) (chloroform/ethanol = 9:1) Analysis: Calculated for C, ^H.^N^O^Se (molecular weight: 339) C % = 49.6 ; H % = 4.76; N % = 8.26 ; found: C % = 48.8 ; H % = 4.6 ; N % = 8.1 . Example 55 Preparatin of 4,4-dimethylselenadiazolo- /5 , -c/-dioxolo/4,5-e/-4H-/I/benzopyraπ 2.77 g (10 mmoles) of 2,2-dimethyl-6,7-methyle- nedioxy-4-chromaπone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture Is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 87-104 C. R f = 0.83 (benzene/ethyl acetate = 1:1) 0.75 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.75 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, 2 H, j -N ^ O- j Se (molecular weight: 309) C % = 46.64; H H % = 3.26; N % = 9.07 ; found: C % = 46.4 H = 3.0 N % = 9.17 Example 56 Preparation of ,4-dimethylselenadiazolo- /5,4-c/-dioxolo/4,5-f/-4H-/I/beπzopy an 2.77 g (10 mmoles) of 2,2-dimethyl-7,8-methyle- πediαxy-4-chromaπone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 151-154 °C. ~ = 0.64 (benzene/ethyl acetate = 1:1) 0.7 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.73 (chloroform/ethaπol = 9:1) Analysis : Calculated for C 12 H 1Q N 2 0 3 Se (molecular weight: 309) C % = 46.64; H = 3.26; N = 9.07 found: C % = 46.4 ; H = 3.0 ; N = 9.1 Example 57 Preparation of 4,4-dimethylseleπadiazolo- /5 ,4-c/-dioxano/2,3-f/-4H-/1/benzopyran 2.91 g (10 mmoles) of 2,2-dimethyl-7 ,8-dioxano- -4-chromaπoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cy ' cli- zatioπ.) The oily residue is crystallized to give the title compound, m.p.: 127-131 C. R f = 0.6 (benzene/ethyl acetate = 1:1) 0.73 (benzene/ethyl acetate/glacial acetic acid = . " = 7:3:1) 0.55 (chloroform/ethanol = 9:1) Analysis: Calculated for C- ^ H^f^O- j Se (molecular weight: 323) C% = 48.34; H = 3.75; N % = 8.67; found: C % = 48.0 ; H % = 4.1 ; N % = 8.7 . Example 58 Preparation of 4 ,4-dimethylselenadiazolo- /5,4-c/-dioxano/2,3-e/-4H-/I/benzopyran 2.91 g (10 mmoles) of 2,2-dimethyl-6,7-dioxano- -4-chromaπαπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cycliza- tion.) The oily residue is crystallized to give the title compound, m.p.: 102-106 C. R F = 0.64 (benzene/ethyl acetate = 1:1) 0.76 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.64 (chloroform/ethanol = 9:1) Analysis: Calculated for C, ,H..^N^O- j Se (molecular weight: 323) C % = 48.34; H % = 3.75; N % = 8.67 ; found: C % = 48.4 ; H % = 4.1 ; N % = 8.3 . Example 59 Preparation of 7-propargyloxy-4,4,9-trimethyl- -4H-selenadiazolo/5,4-c//I/benzopy an 3.01 g (10 mmoles) of 7-propargylαxy-2,2,5- -trimethyl-4-chromaπone semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound, m.p.: 63-65 C. R f - 0.69 (benzene/ethyl acetate = 1:1) 0.72 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.76 (chloroform/ethanol = 9:1) Analysis: Calculated for (molecular weight: 333) C % = 54.1 ; H % = 4.24; N % = 8.41 ; found: C % = 54.0 ; H % = 4.4 ; N % = 8.3 . Example 60 Preparation of 7-propargyloxy-4,4,6-trimethyl- -4H-selenadiazolo/5,4-cZ/I/benzopy an 3.01 g (10 mmoles) of 7-propargylαxy-2,2,8- -trimethyl-4-chromaπoπe semicarbazone in 20 ml of glacial acetic acid are oxidized by portionwise adding 1.33 g (12 mmoles) of selenium dioxide while heating and stirring. After cessation of the gas evolution and TLC control, the reaction mixture is evaporated. (The recovered glacial acetic acid may repeatedly be used for cyclization.) The oily residue is crystallized to give the title compound m. p 113-115 R f = 0.74 (benzene/ethyl acetate = 1:1) 0.74 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethanol = 9:1) Analysis : Calculated for C-, ,-H, 4 N 2 0 2 Se (molecular weight: 333) C % = 54.1 H = 4.24; N = 8.41 found 54.21; H % = 4.04; N % = 8.5 Example 61 Preparation of 4-phenyl-4H-selenadiazolo- /5,4-c//I7benzopyran A mixture containing 2.87 g (10 mmoles) of 2-pheπyldihydrobeπzopyraπ-3-seleπone , 1.11 g (11 mmoles) of triethylamine, and 2.18 g (11 mmoles) of tosyl azide in 15 ml of acetonitrile is kept at 22 °C for one day, then evaporated and the residue is recrystallized to give the title compound in a yield of 94 % m.p. : 168- -171 °C. R- = 0.22 (benzene/ethyl acetate = 1:1) 0.60 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.52 (chloroform/ethanol = 9:1) Analysis : Calculated for C, eH. Q N 2 0Se (molecular weight: 313) C % = 57.51; H \ = 3.22; N % = 8.95 ; found: C % = 57.43; H % = 3.30; N % = 9.12 . Example 62 Preparation of 4,4-dimethyl-7-methoxy-4H-seleπa diazolo/5 ,4-c//I/benzopyran A mixture containing 2.69 g (10 mmoles) of 2,2-dimethyl-7-rnethoxy-dihydrobenzopyran-3-selenoπe, 2.18 g (11 mmoles) of tosyl azide and 1.11 g of triethyl¬ amine in 15 ml of dioxaπe is stirred at 20 to 25 °C for 20 hours, then evaporated and the residue is re¬ crystallized to give the title compound in a yield of 92 %, m.p. : 57-60 °C. R ~ = 0.68 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.78 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, 2 H. 2 N 2 0 2 Se (molecular weight: 295) C % = 48.85; H % = 4.10; N % = 9.49 ; found: C % = 49.0 ; H % = 4.1 ; N % = 9.6 . Example 63 Preparation of 7,8-dimethoxy-4,4-dimethyl- -4H-selenadiazolo/5,4-c//I/beπzopyran A mixture containing 29.9 g (0.1 mole) of 6,7-dimethoxy-2,2-dimethyldihydrobenzopyran-3-seleπone, 11.1 g (HO mmoles) of triethylamine and 21.8 g (110 mmoles) of tosyl azide in 150 ml of acetoπitrile is kept at 22 C for 22 hours, then evaporated and the residue is recrystallized to give the title compound in a yield of 92 %, m.p.: 98-100 °C. R = 0.62 (benzene/ethyl acetate = 1:1) 0.69 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethanol = 9:1) Analysis: Calculated for c 3 H i4 N 2°3 Se (molecular weight: 325) C = 48.04; H % = 4.34; N % = 8.62 ; found: C % = 48.3 ; H % = 4.4 ; N % = 8.6 . E xamp le 64 Preparation of ,4-dimethyl-7-ethoxy-8-methoxy- -4H-selenadiazolo/5,4-c// /benzopyran A mixture containing 3.13 g (10 mmoles) of 2,2-dimethyl-7-ethoxy-6-methoxydihydrobeπzopyraπ-3- -seleπone, 1.11 g (11 mmoles) of triethylamine and 2.18 g (11 mmoles) of tosyl azide in 20 ml of aceto- nitrile is kept at 20 °C for 20 hours. The solvent is recovered by evaporation under vacuum and the resi- due is crystallized to give the title compound, m.p. : 84-87 °C. R, = 0.68 (benzene/ethyl acetate = 1:1) 0.68 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethanol = 9:1) Analysis : Calculated for C, 4 H. ,N 0-,Se (molecular weight: 339) C % = 49.6 ; H % = 4.76; N % = 8.26 ; found: C % = 49.4 ; H % = 4.9 ; N % = 8.3 . Example 65 Preparation of 6 ,7-dirnethoxy-4 , 4-dimethyl- -4H-selenadiazolo/5,4-c//I/beπzopyran 2.18 g (11 mmoles) ' of tosyl azide are added to the solution of 2.99 g (10 mmoles) of 7 , 8-dimethoxy- -2 , 2-dimethyldihydrobeπzopyraπ-3-seleπoπe and 1.11 g (11 mmoles) of N-methylmorphαliπe in 15 ml of tetrahydro- furan, the mixture is kept at 15 to 25 °C for one day, then the solvent is recovered by evaporation and the product is recrystallized to give the title compound, m.p. : 225-227 °C. R f = 0.66 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethaπol = 9:1) Ana lysis : Calculated for C, -.H, . N 2 0,Se (molecular weight: 325) C % = 48.04; H % = 4 . 34 ; N % = 8 . 62 ; found: C % = 48.2 ; H % = 4 . 3 ; N % = 8 . 8 . Example 66 Preparation of 7 , 9-dlmethoxy-4,4-dimethyl- -4H-selenadiazolo/5, 4-c//I/benzopyr π A mixture of 2.99 mg (1 mmole) of 5 ,7-dimethαxy- -2,2-dimethyl-dihydrobeπzopyraπ-3-seleπone , 0.111 g of triethylamine and 218 mg of tosyl azide in 3.0 ml of acetonitrile is kept at 20 to 25 °C for one day, then diluted with water, the precipitate is filtered and recrystallized to give the title compound in a yield of 88 %, m.p. : 113-114 °C. R f = 0.67 (benzene/ethyl acetate = 1:1) 0.66 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethaπol = 9:1) Analysis : Calculated for C,,H..N 2 0,Se (molecular weight: 325) C % = 48.04; H % = 4.34; N % = 8.62 ; found: C % = 48.0 ; H % ~ 4.3 ; N % = 8.7 . Example 67 Preparation of 7-methoxy-4 ,4 ,6-trimethyl- -4H-seleπadiazolo/5 ,4-c//I/benzopyraπ A mixture of 2.83 g (10 mmoles) of 7-methoxy- -2,2, 8-trimethyldihydrobenzopyraπ-3-selenone, 1.1 g of N-methylpiperidine and 2.18 g of tosyl azide in 15 ml of acetonitrile is kept at 20 to 25 °C for 20 hours, then the solvent is recovered by evaporation under vacuum and the residue is recrystallized to give the title compound in a yield of 89 m .p 50-53 R f = 0.73 (benzene/ethyl acetate = 1:1) 0.77 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.77 (chloroform/ethanol = 9:1) Analysis : Calculated for C, 3 H 14 N 2 0 2 Se (molecular weight: 309) C % = 50.53; H % = 4.57; N % = 9.07 ; found: C % = 50.3 ; H % = 4.5 ; N % = 9.2 . Example 68 Preparation of 7-methoxy-4,4,9-trimethyl- -4H-selenadiazolo/5,4-c//I/beπzopyran A solution of 2.83 g (10 mmoles) of 7-methoxy- -2,2,5-trimethyl-dihydrobeπzopyraπ-3-selenoπe, 1.0 g of piperidine and 2.18 g of tosyl azide in 25 ml of ethanol is reacted at 25 °C for 24 hours, then the solvent is recovered by distillation under vacuum and the residue is recrystallized to give the title com¬ pound in a 96 % yield, m.p.: 90-93 °C. R = 0.72 (benzene/ethyl acetate = 1:1) 0.75 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.75 (chloroform/ethanol = 9:1) Analysis: Calculated for C,,H, ^ 2 0 2 Se (molecular weight: 309) C = 50.53; H % = 4.57; N % = 9.07 ; found: C % = 50.7 ; H % = 4.5 ; N % = 9.2 . Example 69 Preparation of 7-proparqyloxy- ,4,9-trimethyl- -4H-selenadiazolo/5,4-c//I/benzopyran 3.07 g (10 mmoles) of 7-propargyloxy-2,2,5- -trimethyldihydrobenzopyran-3-selenoπe are reacted with 2.18 g of tosyl azide and an equimolar amount of pheπyllithium in 30 ml of ether at 20 °C. The reac- tion is followed by TLC. After the completion of the reaction, the solvent is evaporated under vacuum, the residue is dissolved in chloroform, washed with acid and then with saturated sodium chloride solution, then dried and evaporated to give the title compound In a yield of 76 %, m.p.: 63-65 C. R f = 0.69 (benzene/ethyl acetate = 1:1) 0.72 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.76 (chloroform/ethanol = 9:1) Analysis: Calculated for C, ,-H, .N 2 0 2 Se (molecular weight: 333) C % =.54.1 ; H % = 4.24; N % = 8.41 ; found: C % = 54.0 ; H % = 4.4 ; N % = 8.3 . Example 70 Preparation of ,4-dimethyl-7,8-dipropargyl- oxy-4H-selenadiazolo/5,4-c7/I/benzopyraπ 3.47 g (10 mmoles) of 2,2-dimethyl-6,7-di- propargyloxydihydrobenzopyran-3-selenoπe are reacted with 0.95 g (11 mmoles) of piperidine and 2.18 g (11 mmoles) of tosyl azide in 25 ml of dichloromethaπe at 20 to 25 °C. The completion of the reaction is detected by TLC. Then, the solvent is evaporated and the residue. is recrystallized to give the title compound in a yield of 85 %, m.p. : 78-81 °C. R. = 0.71 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, 7 H..N 2 0-.Se (molecular weight: 373) C % = 54.74; H % = 3.78; N % = 7.51 ; found: C % = 54.4 ; H % = 4.0 ; N % = 7.4 . E x amp le 71 Preparation of 4,4-dimethyl-8-ethoxy-7-methoxy- -4H-selenadiazolo/5,4-c//I/benzopyran A mixture containing 3.13 g (10 mmoles) of 2,2-dimethyl-6-ethoxy-7-methoxydihydrobenzopyran-3- -seleπone, 0.65 g (11 mmoles) of trimethylamiπe, 2.18 g (11 mmoles) of tosyl azide and 30 ml of acetonitrile is reacted at 20 to 25 °C for 20 hours. Then, the solvent is recovered by evaporation under vacuum and the residue is recrystallized to give the title compound in a yield of 88 %, m.p. : 70-72 °C. R f = 0.69 (benzene/ethyl acetate = 1:1) 0.67 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethaπol = 9:1) Analysis: Calculated for C, H, ^N^O- j Se (molecular weight: 339) C % = 49.6 ; H % = 4.76; N % = 8.26 ; found: C % = 48.8 ; H % = 4.6 ; ft % = 8.1 . Example 72 Preparation of 4,4-dimethylselenadiazolo- /5 ,4-c/-dioxolo/4,5-f/-4H-/I/benzopyran A mixture of 2.83 g (10 mmoles) of 2,2-di- methyl-7,8-methyleπedioxydihydrobeπzopyran-3-seleπoπe, 0.81 g (11 mmoles) of diethylamine, 2.18 g (11 mmoles) of tosyl azide and 20 ml of ethanol is reacted. The reaction is followed by TLC. After completion of the reaction, the solvent is recovered by evaporation and the residue is recrystallized to give the title compound in a yield of 94 %, m.p.: 151-154 °C. R f = 0.64 (benzene/ethyl acetate = 1:1) 0.7 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.73 (chloroform/ethaπol = 9:1) Analys is : Calculated for C^H.g ^Se (molecular weight: 309) C % = 46.64; H % = 3.26; N % = 9.07 ; found: C % = 46.4 ; H = 3.0 ; N % = 9.1 . Example 73 Preparation of 4,4-dimethylseleπadiazolo- /5,4-c/-dioxaπo/2,3-e/-4H-/I/benzopyraπ A mixture of 2.97 g (10 mmoles) of 2,2-dlmethyl- -6,7-dioxanodihydrobenzopyran-3-selenone, 25 ml of diethylamiπe and 2.18 g (11 mmoles) of tosyl azide is reacted. The reaction is followed by TLC. After completion of the reaction, the solvent is evaporated (and again used). The residue is recrystallized to give the title compound in a yield of 92 %, m.p.: 102- -106 °C. R f = 0.64 (benzene/ethyl acetate = 1:1) 0 .76(benzeπe/ethyl acetate/glacial acetic acid . = = 7:3:1) 0.64 (chloroform/ethaπol = 9:1) Analysis: Calculated for (molecular weight: 323) C % = 48.34; H % = 3.75; N % = 8.67 ; found: C % = 48.4 : H % = 4.1 ; N % = 8.5 . Example 74 Preparation of 4,4-dimethylseleπadiazolo- /5,4-c/- ioxolo/4,5-e/-4H-/I/ben opyran A mixture of 2.83 g (10 mmoles) of 2,2-dimethyl- -6,7-methylenedioxydihydrobeπzopyran-3-selenoπe, 0.94 g (11 mmoles) of piperidine, 2.18 g of tosyl azide and 20 ml of acetonitrile is reacted at 20 to 25 °C for 20 hours. After completion of the reaction, the solvent is evaporated and again employed. The residue is re- crystallized to give the title compound in a yield of 96 %, m.o. : 97-104 °C. R = 0.83 (benzene/ethyl acetate = 1:1) 0.75 (benzene/ethyl acetate/glacial acetic acid = 7:3:1) 0.75 (chloroform/ethanol = 9:1) Analysis: Calculated for C, 2 H. n N 2 0-,Se (molecular weight: 309) C % = 46.64; H % = 3.26; N % = 9.07 ; found: C % = 46.4 ; H % = 3.0 ; N % = 9.17 . Example 75 Preparation of 4,4-dimethylselenadiazolo- /5,4-c/-dioxano/2,3-f/-4H-/I/benzopyran A mixture containing 2.97 g (10 mmoles) of 2,2-dimethyl-6,7-dioxanodihydrobeπzopyran-3-selenone, 1.11 g (11 mmoles) of triethylamine, 2.18 g (11 mmoles) of tosyl azide and 20 ml of acetonitrile is reacted at 20 °C for 20 hours. Then, the solvent is recovered by evaporation under vacuum and the product is re¬ crystallized to give the title compound in a yield of 82 %, m.p. : 127-131 °C. R f = 0.6 (benzene/ethyl acetate = 1:1) 0.73 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.55 (chloroform/ethaπol = 9:1) Analysis: Calculated for C-^H. 2 N 2 0--Se (molecular weight: 323) C % = 48.34; H H % = 3.75; N N % = 8.67 ; found: = 48.0 H 4-.1 N = 8.7 Example 76 Preparation of 7-propargyloxy-4,4,6-trimethyl- -4H-selenadiazolo/5,4-c//I/beπzopyran A mixture containing 3.07 g (10 mmoles) of 7-propargyloxy-2,2,8-trimethyldihydrobenzopyran-3-sele- noπe, 1.11 g (11 mmoles) of triethylamine, 2.18 g (11 mmoles) of tosyl azide and 25 ml of metanol is reacted at 20 to 25 °C for 24 hours. Then, the solvent is re¬ covered by evaporation under vacuum and the product is recrystallized to give the title compound in a yield of 91 %, m.p. : 113-115 °C. R = 0.74 (benzene/ethyl acetate = 1:1) 0.74 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.74 (chloroform/ethanol = 9:1) Analysis : Calculated for C, ,-H, 4 N 2 0,-Se (molecular weight: 333) C % = 54.1 ; H % = 4.24; N % = 8.41 ; found: C % = 54.21; H % = 4.04; N % = 8.5 . Example 77 Preparation of 4-phenyl-4H-selenadiazolo- /5,4-c//I7benzothiopyran 2.18 g (11 mmoles) of tosyl azide are added to a mixture of 3.03 g (10 mmoles) of 2-pheπyldihydro- beπzothiopyran-3-seleπoπe, 1.11 g (11 mmoles) of triethyl- amine and 30 ml of dichloromethaπe, then the mixture is let stand for 20 hours. The solvent is recovered by evaporation and the residue is recrystallized to give the title compound in a yield of 82 %, m.p.: 55- -58 °C. R = 0.73 (benzene/ethyl acetate = 1:1) 0.78 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.79 (chloroform/ethaπol = 9:1) Analysis: Calculated for C 15 H 1Q N 9 SeS (molecular weight: 329) C % = 54.765 H % = 3.0 ; N % = 8 .52 5 found: C % = 55.1 H % = 3.13; N % = 8.38 . E x amp l e 78 Preparation of 7 ,8-dimethoxy- ,4-dimethyl- thiadiazolo/5 " ,4-c//I/benzopyraπ A mixture containing 2.52 g (10 mmoles) of 6,7-dimethαxy-2,2-dimethyl-3,4-dihydro-2H-beπzopyraπ- -3-thioπe, 0.96 g (11 mmoles) of mcrpholiπe, 2.18 g (11 mmoles) of tosyl azide and 25 ml of ethanol is reacted at 20 to 25 °C for 24 hours. The solvent is recovered by evaporation and the residue is recrystalli- zed to give the title compound in a yield of 79 , m.p. : 118-120 °C. R f = 0.62 (benzene/ethyl acetate = 1:1) 0.59 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethanol = 9:1) Analysis: Calculated for C, ,H, 4 2 0--Se (molecular weight: 278) C % = 56.16; H % = 5.07; N % = 10.08; found: C % = 56.4 ; H = 5.0 ; N % = 10.20. Example 79 Preparation of 6 ,7-dimethoxy-2 ,2-dimethyl- -3,4-dihydro-2H-benzopyraπ-3-thione 2.36 g (10 mmoles) of 6 ,7-dimethoxy-2,2- -dimethyl-3,4-dihydro-2H-beπzopyraπ-3-oπ and 4.44 g (20 mmoles) of phosphorus peπtasulfide are refluxed in 50 ml of pyridine for 3 hours, and after completion of the reaction, the mixture is poured into 250 ml of ice-water. The precipitate is thoroughly triturated, filtered and dried to give the title compound in a yield of 88 %. IR: 2960, 1620, 1520, 1260, 865 cm -1 X H-NMR (5 " ppm, DMSO-dg): 1.8 (6H), 3.6 (6H), 4.2 (2H), 7.2 (1H), 7.4 (1H) Analysis Calculat e d for (molecular weight: 252) C % = 61.96; H = 6.4 ; S % = 12.7 ; found: C % = 62.0 ; H = 6.51; S % = 11.68. Example 80 Preparation of 6,7-dimethoxy-2,2-dimethyl- -3,4-dihydro-2H-benzopyran-3-seleπone 2.36 g (10 mmoles) of 6,7-dimethoxy-2,2-di- methyl-3 ,4-dihydro-2H-benzopyran-3-one are refluxed with 9.2 g (20 mmoles) of phosphorous peπtaselenide in 50 ml of pyridine for 3 hours, then poured in 200 ml of ice-cold 1:1 hydrochloric acid, and the product separated is extracted into chloroform , or benzene. The combined organic phase Is dried over anhydrous calcium chloride and evaporated to give the title com¬ pound in a yield of 92 %, which is pure enough for the next step. IR: 2960, 1615, 1530, 1100, 870 cm "1 L H-NMR ( cT, ppm, DMSO-dg) : 2.0 (6H) , 3.6 (6H) , 4.2 (2H), 7.3 (1H), 7.5 (1H) Analysis: Calculated for C 1 H,.0,Se (molecular weight: 299) C % = 52.22; H % = 5.39; found: C % = 53.0 ; H % = 5.46; Example 81 Preparation of 4,4-dimethyl-7-methoxy-4H- selenadiazolo/5,4-c//I/benzopyran A solution of 2.81 g (10 mmoles) of 3-hydroxy- -l-(2'-hydroxy-4-methoxypheπyl)-3-methylbutaπoπ-l-oπe semicarbazone in 25 ml of glacial acetic acid is boiled for one hour, then 1.11 g (10 mmoles) of selenium dioxide are portionwise added under continuous heating and stirring. The stirring and heating are continued until the gas evolution ceases and the starting substance disappears (as detected by TLC). Then, the acetic acid is evaporated under vacuum and the residue is recrystal¬ lized from ethanol or from a hydrocarbon to give the title compound, m.p. : 57-60 C. R f = 0.68 (benzene/ethyl acetate = 1:1) 0.71 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.78 (chloroform/ethaπol = 9:1) Analysis : Calculated for C, 2 H, N 2 0 2 Se (molecular weight: 295) N % = 9.49; found: N .% = 9.6 . The following co puπds were prepared by using method • described in Example 81: 4-Phenyl-4H-seleπadiazolo/5 ,4-c//I/beπzopyraπ , m.p. : 168-171 °C; 4,4-dimethyl-7-ethoxy-8-methoxy-4H-selenadiazolo/5,4-c/- /I/benzopyran , m.p. :84-87 C; 6,7-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I/- beπzopyraπ, m.p. : 125 - 127 °C; 7,9-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/beπ- zopyraπ, m.p. : 113-114 °C; 7-methoxy-4,4,6-trimethyl-4H-seleπadiazolo/5,4-c//I/- benzopyran, m.p. : 50-53 °C; 7-methoxy-4,4,9-trimethyl-4H-selenadiazolo/5,4-c//I7- benzopyran, m.p. : 90-93 C; 7-propargyloxy-4,4,9-trimethyl-4H-sεleπadiazolo/5,4-c/- /I/benzopyraπ, m.p.: 63-65 C; 4,4-dimethyl-7,8-dipropargyloxy-4H-selenadiazolo/5,4-c7- /I/beπzopyran , m.p. : 78-81 C; and ,4-dimethyl-8-ethoxy-7-methoxy-4H-seleπadiazolo/ ,4-c//17 be nzop yr an , m . p . : 70 -72 C . m .p. 98-100 °C Example 82 Preparation of 4 ,4-dimethylselenadiazolo- /5,4-c/-dioxolo/4,5-f/-4H-/I/benzopyraπ A solution containing 3.27 g (10 mmoles) of 5-(l'-hydroxy-l '-methyl)ethyl-4-(2-hydroxy-3,4- -methylenedioxy)pheπyl-l,2,3-seleπadiazole in 30 ml of glacial acetic acid is boiled for one hour, then set aside overnight. Then, the ?cstic acid is recovered by distillation (under atmospheric or reduced pressure) and the residue is recrystallized or dissolved in a water-immiscible solvent (e.g. chloroform) and washed with water to give the title compound, m.p.: 151-154 °C. R f = 0.64 (benzeπe/ethy 1 acetate = 1:1) 0.70 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.73 (chloroform/ethanol = 9:1) Analysis: Calculated for C, 2 H. -t^O^Se (molecular weight: 309) C % = 46.64; H % = 3.26; N % = 9.07; found: C % = 46.4; H % = 3.0; N % = 9.1. The following compounds were prepared by using the process described in Example 82: 7 , 8-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5 ,4-cZ/I/- beπzopyraπ, m.p.: 98-100 °C; 4,4-dimethylseleπadiazolo/5,4-c/-dioxaπo/2,3-e/-4H-/I/- benzopyraπ, m.p.: 102-106 °C; 4,4-dirπethylselenadiazolo/5,4-c/-dioxolo/4,5-e/-4H-/I/- benzopyraπ, m.p.: 87-104 °C; 4,4-dimethylseleπadiazolo/_5,4-c/-dioxano/2,3~f/-4H-/I/- beπzopyraπ, m.p.: 127-131 °C; 7-prαpargyloxy-4,4,6-trimethyl-4H-seleπadiazolσ/5,4-c//IZ- beπzopyraπ, m.p.: 113-115 °C; r 4_( i me thyl-8-ethoxy-7-methoxy-4H-selεπadiazolo/5,4-c/- /IZ-beπzopyraπ , m.p.: 70-72 °C; 4,4 -dimethyl-7-ethoxy-8-methoxy-4H-seleπadiazolo/5,4-c/- /I/benzopyran , m.p. : 84-87 °C; 4,4-dimethyl-7-methαxy-4H-selenadiazolα/5,4-c//I/beπzo- pyran , m.p . : 57-60 °C ; 6,7-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5,4-c//I/- benzopyran, m.p. : 125-127 °C; and 7-propargyloxy-4,4,9-trimethyl-4H-selenadiazolo/5,4-c//I/ beπzopyraπ, m.p. : 63-65 C. Example 83 Preparation of 4-pheπyl-4H-selenadiazoIo- /5,4-c//I/benzothiopyran A mixture containing 3.90 g (10 mmoles) of N-nitroso-N-(thiaflavaπon-3-seleπoπ-4-yl)urea, 50 ml of tetrahydrofuran and 10 ml of 10 % potassium hydroxide solution is stirred at 25 °C for 2 hours, then the solvent is evaporated under vacuum and the residue is purified by chromatography on a Kieselgel column to give the title compound, m.p.: 55-58 °C. R f = 0.73 (benzene/ethyl acetate = 1:1) 0,78 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.79 (chloroform/ethaπol = 9:1) Analysis: Calculated for 0-,,-H, η N^SSe (molecular weight: 329) N % = 8.52 ; found: N % = 8.38 . The following compounds were prepared by using the process described in Example 83: 4-Phenyl-4H-selenadiazolo/5,4-cZ/I/beπzopyraπ, m.p. : 168-171; 4,4-dimetπyl-7-methoxy- H-selεπadiazolo/5,4-c//I/benzo- pyran, m.p.: 57-60 α C. 7,8-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c//I/- beπzopyran, m.p.: 98-100 °C; ,4-dimethyl-7-ethoxy-8-methoxy-4H-seIenadiazolo/5,4-c/- /I/benzopyran, m.p.: 84-87 °C. 6,7-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5 ,4-c//I/- beπzopyran, m.p.: 125-127 °C; 7,9-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5 ,4-c//I/- beπzopyran, m.p.: 113-114 °C; 7-methoxy-4,4,6-trimethyl-4H-selenadiazolo/5,4-c//I/- beπzopyran, m.p.: 50-53 °C; 7-methoxy-4,4,9-trimethyl-4H-seleπadiazolo/5 ; 4-c//I/- benzopyraπ, m.p. : 90-93 °C; 7-propargyloxy-4,4,9-trimethyl-4H-seleπadiazolo/5,4-c/- /I/beπzopyran , m . p . : 63-65 C ; 4 , 4-d imethyl -7 , 8 -dipropa rgyloχi-4H- se len ad i azolo/ 5 , 4-c/- /I/beπzopyraπ , m.p. : 78-81 C; 4,4-dimethyl-8-ethoxy-7-methoxy-4H-selenadiazolo/5,4-c/- /ϊ/beπzαpyran , m.p. : 70-72 C; 4,4-dimethylseleπadiazolo/5,4-c/-dioxolo/4,5-f/-4H- -/I/beπzopyraπ, m.p. : 151-154 °C; 4,4-dimethylseleπadiazolo/5,4-c/-diσxaπo/2,3-e/-4H- -/I/beπzopyraπ , m.p. : 102-106 °C; 7-ρrαpargyloxy-4,4,6-trimethyl-4H-seleπadiazolo/5,4-c/- /I/beπzopyran , m.p. : 113-115 C; and 7,8-dimethoxy-4,4-dimethyl-4H-thiadiazolo/5,4-c//I/benzo- pyran, m.p. : 118-120 C. Example 84 Preparation of 7 , 8-dimethoxy-4 , 4-dimethyl- -4H-selenadiazolo/5,4-c//I/beπzopyraπ A mixture containing 3.11 g (10 mmoles) of 7,8-dimethoxy-4H-selenadiazolo/5,4-c//I/beπzopyraπ- -4-oπe in 50 ml of anhydrous ether is added to the solution of 20 mmoles of methyl magnesium iodide in 20 ml of ether, then the mixture is refluxed for 2 hours under stirring and then evaporated. To the residue 25 ml of glacial acetic acid are added, the mixture is refluxed for one hour and then mixed with water and extracted with chloroform. The organic phase is washed with sodium carbonate solution, dried and evapor¬ ated to give the title compound in a yield of 85 % , m.p. : 98-100 °C. R~ = 0.62 (benzene/ethyl acetate = 1:1) 0.69 (benzene/ethyl acetate/glacial acetic acid = = 7:3:1) 0.86 (chloroform/ethanol = 9:1) Analysis: Calculated for C 13 H 14 N 2 Q 3 Se ( m °l ecu l ar weight : 325 ) C % = 48.04; % = 4.34; N = 8.62 found: C % = 48.3 ; % = 4.4 : N = 8.6 The following compounds were prepared by using the process described in Example 84: 4,4-dimethyl-7,8- ipropargyloxy-4H-selenadiazolo/5,4-c/- /I/benzopyraπ, m.p.: 78-81 °C; 4,4-dimethyl-8-ethoxy-7-methαxy-4H-seleπadiazolo/ ,4-c/- /I/benzopyraπ, m.p.: 70-72 °C; 7,8-diethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c7/I7- benzopyran, m.p.: < 50 C; 7-allyloxy-4,4-dImethyl-4H-seleπadiazolo/5,4-c7/I/- benzopyran, m.p.: 63-65 °C; 7,8-dimethoxy-4,4-dimethyl-4H-thiadiazolo/5,4-c7/I7benzo- pyran, m.p.: 118-120 °C; 7-propargyloxy- ,4,6-trimethyl-4H-selenadiazolo/5,4-c7- /I/beπzopyraπ, m.p.: 113-115 °C; 7-propargyloxy-4,4,9-trimethyl-4H-selenadiazαlα/5,4-c/- /I/beπzopyraπ, m.p.: 63-65 °C; 4,4-dimethyl-7-propargyloxy-4H-selenadiazolo/5,4-c//I/- beπzopyran, m.p.: 83-85 °C; 4,4-dimethyl-7-ethoxy-8-methoxy-4H-seleπadiazolo/5,4-c/- /I/beπzopyran, m.p.: 84-87 °C; 4,4-dimethyl-7-ethoxy-4H-seleπadiazolo/5,4-c7/I/benzo- pyraπ, m.p.: 104-106 °C; 7,9-dimetho y-4,4-dimethyl-4H-seleπadiazolo/ ,4-c7/I7- benzopyran, m.p.: 113-114 °C; 7-methoxy-4,4,9-trimethyl-4H-seleπadiazolo/5,4-c//I/- benzopyran, m.p.: 90-93 °C; 6,7-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5 ,4-c//I/- beπzopyran, m.p.: 30-32 °C; and 7-methoxy-4,4,6-trimethyl-4H-selenadiazαlo/5,4-c//I/- benzopyran, m.p.: 50-53 °C. Biological action The effects of the compounds of the invention were studied by using the following biological test systems: 1) the in vivo insecticide and allatocide action on freshly shedded L4-stage locust (Locusta migra- toria) nymphs; 2) the in vitro allatocide action on the corpora allata taken from freshly shedded L5-stage locust nymphs by using the method of Shoeπeveld (1982); 3) the nematocide action on synchronized Ll-stage larvae of Caenorhabditis elegaπs Cb 678 strain; 4) the insecticide action on the large white butter¬ fly (Pieris brassicae), fall webwor (Hyphantria cunea), potato beetle (Leptiπotarsa decemlineata) and pea green-fly aphis (Acyrthosiphon pisum) ; 5) in other bactericidal, fungicidal and iπsecticidal including acaricidal tests. 1) In vivo tests on locusts The locusts were bred and kept according to the international standards, in rooms thermostated at 29 °C under a stable moisture content, with a day- -part change of the temperature. The L4 nymphs of the locust (Locusta migratoria) freshly shedded within 24 hours were topically treated with the test compounds dissolved in acetone. The animals were anaesthetized by carbon dioxide. The control animals were treated only with acetone. The locusts were daily observed for 21 days and the time and number of the perishmeπts and sheddiπgs were registered. After 21 days, the presence of the eventual adultoids were also investigated. The effects of the compounds tested were as follows: 4,4-dimethyl-7-methoxy-4H-seleπadiazolo/5 , -c//I/benzo¬ pyran: On using a dose of 50 /ug/aπimal, one out of 40 animals only survived, whereas the perishmeπt was total by using a higher dose. 4,4-dimethyl-7-ethoxy-8-methαxy-4H-selenadiazolα/5,4-c/- /I/beπzopyraπ: The LC ^j , value of this compound is at a dose of 25 to 50 ug/animal. Survival was observed even at a dose of 100 /ug/aπimal. 6,7-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-cZ- /I/beπzopyraπ: Nearly no survival was observed at a dose of 50 /ug/aπimal. 7-Methoxy-4,4,6-trimethyl-4H-selenadiazolo/5,4-c//I/- beπzopyraπ: The lethality is 95 to 100 % by using a dose of 400 or 100 ,ug/aπimal. 2) In vitro CA test These investigations were carried out by using Schoeneveld' s in vitro test (1982). Most of the test compounds were used at four dose levels (5, 10, 50 or 100 /ug/ml of medium) . The surviving glands were not stained by using a vital dye (acridine orange) after 24 hours, whereas the perished organs showed a staining. The results of the in vitro CA test determined by using the above method are summarized in Table 1. T; able 1 results of thi 3 in vitro CA test Compound Results of the measurements LC 50 No. Percentage of survival at /ug/ml 1. 60 20 0 0 1.35. 2. - 44 - 0 1.51 3. - 79 - - 524 4. - 67 - 50 21 5. 100 20 - 0 4 6. - 55 .- 0 ■ 4.3 7. - - - 50 21 8. 100 46 20 11 4.2 9. 100 100 90 63 170 10. 100 100 90 100 423773 11. 75 56 20 ' 20 3.8 12. 100 100 30 0 6.8 13. 100 100 80 78 582 ' l4. + - - - 0 - Notes to Table 1: x These values are expressed as ,ug of selenium. + It is important that no allatocide effect is observed in vitro up to 100 ug. 0: No effect Not determined The chemical names of the numbered compounds in Table 1 are as follows: 1: 4,4-dimethyl-7-methoxy-4H-selenadiazolo/5,4-c/- /I/benzopyran, : 7,8-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c/- /I/beπzopyran, 3: 4-phenyl-4H-seleπadiazαlo/5,4-cZ/I7beπzopyran, 4: 7-methoxy-4,4,6-trirnethyl-4H-seleπadiazolo/5,4-c/- /I7benzopyraπ, : 6,7-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5 ,4-c7- /I/beπzopyraπ, 6: 7-methoxy-4,4,9-trimethyl-4H-seleπadiazolo/5 ,4-c/- /I/benzopyraπ, 7: 7,9-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c/- /I/beπzopyran, 8: 4,4-dlmethyl-7-ethαxy-8-methoxy-4H-seleπadiazolo/ ,4-c_ /I/benzopyraπ, : 4,4-dimethyl-7-propargyloxy-4H-seleπadiazolo/5,4-c/- /I/beπzopyran, 10: 7-propargyloxy-4,4,6-trimethyl-4H-selenadiazolo/5 ,4-c7- /I/benzopyraπ, 11: 4,4-dimethyl-4H-/I,47-dioxaπo/2,3-g7selenadiazolo- /5,4-c//ϊ/beπzαpyraπ, 12. 4,4-dimethyl-4H-/ϊ,4/-dioxano/2,3-h/seleπadiazolo- /5,4-c7/I/benzopyran, 13: 4,4-dimethyl-4H-/I,3/-dioxolo/4,5-g7seleπadiazolo- / ,4-c7/I7beπzopyraπ and 14: selenium dioxide. 3) Study of the nematocide effect Synchronized Ll-stage larvae obtained by the hypochlorite method from Caeπorhabditis elegans (C. elegans, laboratory threadworm) CB 678 strain were put onto NGM agar chilled in the holes of a microtitra- tor sheet (Brenner, 1974) also containing the test substance in the appropriate concentrations. Usually, a dilution in the dose interval between 0 and 1000, or between 0 and 500 /ug/ml, respectively was used. A part of the compounds was subjected to a preceediπg experiment with concentrations of 5, 0, 500 and 5000 ,ug/ml. Four repetitions were carried out for each concentration with 15 to 20 animals for each repetition. The sheets also contained E. coli OP 50 bacterial nutriment. After 48 hours, the number of the living, normally developed animals was determined. The percentage ratio of this number related to the control represents the percentage of the survival. In the majority of the cases, this ratio was useful for the approximately accurate calculation of the LD,- n and LD 5 values. The results of the nematocide test are summariz¬ ed in Table 2. The numbering of the compounds in Table 2 is the same as shown in Table 1. Further substances are as follows: 15: 4,4-dimethyl-7-ethoxy-4H-seleπadiazolo/5,4-c/- /I/benzopyran, 16: KSeCN, 17: 7-allyloxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c/- /I/benzopyran, and 18 : 4,4-dimethyl-4H-/ϊ,3 -dioxolo/4,5-h/seleπadiazolα- /5,4-c//I/benzopyran. Table 2 Results of the nematocide test Order of Compound No LD g5 activity /ug/m 1 8 6.75 27 2 1 7.5 20 3 5 13 49 4 10 19 195 5 2 24 127 6 9 40 673 7 14 79 145 8 13 87 442 9 7 143 220 0 6 143 660 Table 2 (coπtd . ) Order of Compound No. activity 11 4 181 518 12 15 181 975 13 12 222 972 14 16 268 718 15 11 624 3382 17 18 oO c > Calculated for selenium

Claims: What we claim is 1. Compounds of the general formula (I) wherein 1 2 R l and R are independently from each other hydrogen, an uπsubstituted or optionally suitably sub¬ stituted alkyl or aryl group; or R 1 and R 2 together may be a cycloalkyl group; is hydrogen; an optionally protected hydroxyl group; an alkyl, alkoxy, 0-trialkyltin group; a phosphoric acid, thiophosphoric acid or phosphorous acid alkyl or aryl ester -group connected through the oxygen atom; an acyloxy, acyloxyalkoxy, 0-trialkylsilyl , aryloxy, alkenyloxy, alkyπyloxy, cycloalkyloxy , cyclo- alkeπyloxy, cycloalkylalkoxy group; an acyloxy or alkoxy group substituted by phosphoric acid, phosphoπic acid or their esters; or two adjacent R groups together may represent: an -0-(CH 2 ) -0-group, wherein m is 1, 2, 3 or 4; or a condensed aromatic ring; or an -0-(CH 2 ) -(0) - group, wherein m is as defined above and z is 0 or 1; or an -0-P(Cl)-0-. -0-P(0C 2 H 5 )-0-, -0-P=0(0C 2 H 5 )-0-, -0-P=S(0C 2 H 5 )-0-, -0-(C=0)-0-, -0-(C=S)-0- 5 -0-P=0(SC 2 H 5 )-0-, -0-P=S(SC 2 H 5 )-0- or an -0-(S=0)-0- group; or a halogen or a haloalkyl, πitro, amino or suitably substituted amino group; an alkoxy group substituted by an alkylamiπo or a dial- kylamiπo group; or a nitrile, mercapto, op¬ tionally substituted alkylthio group; an optionally ring-substituted aralkyloxy group; an acyl group; or two adjacent R groups together may also represent a -C=C-C(=0)-0- aπd -C=C-C=(CH 3 ) 2 -0- group; is 0, 1, 2, 3 or 4, and these R groups may have, independently from each other, any meaning defined for the R groups, Q is oxygen, sulfur, SO or S0 7 ; Q 2 is sulfur or selenium as well as their salts having valuable biological effects 2. A compound as claimed in claim 1, wherein R 1 and R2 are each a methyl group. 3. A compound as claimed in claim 1 wherein R ,3 i.s a methoxy group. 4. A compound as claimed in claim 1 wherein R is a methoxy group and π is 2. 5. A compound as claimed in claim 1, wherein R 1 and R2 are each a methyl group and R3 means a methoxy group. 6. A compound selected from the group consist¬ ing of 4-pheπyl-4H-seleπadiazolo/5,4-c7/I/benzopyraπ, 4, -dimethyl-7-methoxy-4H-selenadiazolo/5, -c//I/benzo¬ pyraπ, 7,8-dimethoxy-4,4-dimethyl-4H-selenadiazolo/5,4-c7- /I/beπzopyraπ, 4,4-dimethyl-8-ethoxy-7-methoxy-4H-seleπadiazo10/5,4^/- /I/beπzopyraπ, ,4-dimethyl-7-ethoxy-8-methoxy-4H-selenadiazolo/5 ,4-c/- /I/benzopyran, 6,7-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c/- /I7benzopyraπ, 7,9-dimethoxy-4,4-dimethyl-4H-seleπadiazolo/5,4-c//ϊ/- beπzopyraπ , 7-methoxy-4,4,6-trimethyl-4H-selenadiazolo/5,4-c//I/- benzopyran, 5 7-methoxy-4,4,9-trimethyl-4H-seleπadiazolo/5,4-c//I/- benzopyraπ , 7-propargyloxy-4,4,9-trimethyl-4H-selenadiazolo/5 ,4-c/ /I/beπzopyraπ , 4,4-dimethyl-7,8-dipropargyloxy-4H-seleπadiazolo/5,4-c/- 0 /I/benzαpyraπ , 4,4-dimethylseleπadiazolo/5,4-c/-dioxolo/4,5-f/-4H- -/I/beπzopyraπ , 4,4-dimethylseleπadiazolo/3,4-c/-dioxaπo/2,3-e/-4H- -/I/beπzopyraπ , 5 4,4-dimethylseleπadiazolo/5,4-c/-dioxolo/4,5-e/-4H- -/I/benzαpyraπ , 4,4-dimethylsεleπadiazolα/5,4-c/-dioxaπo/2,3-f/-4H- -/I/beπzopyran , 7-propargyloxy-4,4,6-trimethyl-4H-selenadiazolo/5 ,4-c_7- 0 /I/beπzopyraπ , 4-pheπyl-4H-seleπadiazolo/5,4-c//I/beπzothiopyraπ, 7,8-dimethoxy-4,4-dimethyl-4H-thiadiazolo/5,4-c//I/- beπzopyraπ and the salts of these compounds. 5 7. A fungicide, nematocide, acaricide, bactericide and insecticide composition which comprises as active ingredient a 4H-selenadiazolo/5 , 4-c//I/benzopyraπ deriva¬ tive of the general formula (I), or a salt thereof in an amount of 0.0C1 to 99.5 % and optionally other 0 active ingredients in admixture with solid and/or liquid carriers and/or vehicles and/or surface active additives, preferably a dispersing, emulsifying or wetting agent and/or other auxiliary materials. 8. A fungicide, nematocide, acaricide, bacteri- c cide and insecticide composition which comprises as active ingredient a 4H-seleπadia.zolo/5 , 4-c//I7beπzothio- pyran derivative of the general formula (I), or a salt thereof in an amount of 0.001 to 99.5 % and optionally other active ingredients in admixture with solid and/or liquid carriers and/or vehicles and/or surface active additives', preferably a dispersing, emulsifying or wetting agent and/or other auxiliary materials. 9. A fungicide, nematocide, acaricide, bacte¬ ricide and insecticide composition which comprises as active ingredient a 4H-thiadiazolo/5 ,4-c//I7benzo- pyran derivative of the general formula (I), or a salt thereof in an amount of 0.001 to 99.5 % and optionally other active ingredients in admixture with solid and/or liquid carriers and/or vehicles and/or surface active additives, preferably a dispersing, emulsifying or wetting agent and/or other auxiliary materials. 10. A fungicide, nematocide, acaricide, bacte¬ ricide and insecticide composition which comprises as active ingredient a 4H-thiadiazolo/3,4-c//I7benzothio- pyraπ derivative of the general formula (I) , or a salt thereof in an amount of 0.001 to 99.5 % and optionally other active ingredients in admixture with solid and/or liquid carriers and/or vehicles and/or surface active additives, preferably a dispersing, emulsifying or wetting agent and/or other auxiliary materials. 11. An acaricide composition, which comprises as active ingredient a compound of the general formula (I) or a salt thereof in an amount of 0.001 to 99.5 % and optionally other active ingredients in admixture with solid and/or liquid carriers and/or vehicles and/or surface active additives, preferably a dispersing, emulsifying or wetting agent and/or other auxiliary materials. 12. A fungicide, nematocide, acaricide, bacte¬ ricide and insecticide composition, which comprises as active ingredient a compound of the general formula (I), wherein Q1 is oxygen, Q2 is selenium and R1 as well as R 2 are each a methyl group, whereas R3 and n are as defined in claim 1 or a salt thereof in an amount of 0.001 to 99.5 % and optionally other active ingre¬ dients in admixture with solid and/or liquid carriers and/or vehicles and/or surface active additives, prefer¬ ably a dispersing .emulsifying or wetting agent and/or other auxiliary materials. 13. A process for the preparation of the novel compounds of the general formula (I), wherein and R are independently from each other hydrogen, an uπsubstituted or optionally suitably sub¬ stituted alkyl or aryl group; or 2 and R together may be a cycloalkyl group; is hydrogen; an optionally protected hydroxyl group; an alkyl, alkoxy, 0-trialkyltio group; a phosphoric acid, thiophosphαric acid or phosphorous acid alkyl or aryl ester group connected through the oxygen atom; an acyloxy, acyloxyalkoxy , 0-trialkylsilyl , aryloxy, alkenyloxy, alkyπyloxy, cycloalkyloxy , cyclo- alkeπyloxy, cycloalkylalkoxy group; an acyloxy or alkoxy group substituted by phosphoric acid, phosphonic acid or their esters; or two adjacent R groups together may represent: an -0-(CH 2 ) -0-group, wherein m is 1, 2, 3 or 4; or a condensed aromatic ring; or an -0-(CH ? ) -(0) - group, wherein m is as defined above and z is 0 or 1; or an -O-P(Cl)- -0-, -0-P(0C 2 H 5 )-0-, -0-P=0(0C 2 H 5 )-0-, -O-P=S(OC 2 H 5 )-O-, -0-(C=0)-0-, -0-(C=S)-0-, -0-P=0(SC 2 H 5 )-0-, -0-P=S(SC 2 H 5 )-0- or an -0-(S=0)-0- group; or a halogen or a haloalkyl, nitro, amino or suitably substituted amino group; an alkoxy group substituted by an alkylamiπo or a dial- kylamiπo group; or a nitrile, mercapto, op¬ tionally substituted alkylthio group; an optionally ring-substituted aralkyloxy group; an acyl group; or two adjacent R groups together may also represent a -C=C-C(=0)-0- and -C=C-C=(CH 3 ) 2 -0- group; is 0, 1, 2, 3 or 4, and these R groups may have, independently from each other, any meaning defined for the R groups, Q! is oxygen, sulfur, SO or S0 2 ; Q 2 is sulfur or selenium as well as their salts having valuable biological effects which comprises transforming a compound of the general formula (IV) , wherein R l R^- R- Q- aπd π are as defined above; and R 4 is hydrogen, an aliphatic cεrboxylic acid ester group, an alkyl or aryl group, or a , -(C=0)-NH-NHR ( (C=S)-NH-NHR' >(C=NH)-NH, -(C=NH)-(NH-NH 2 ) or an ■ S0 -R group ; is an optionally substituted alkyl or aryl group or -(C=0)-NH 2 group; to a benzopyran or benzothiopyran derivative of the general formula (I) and, if desired, converting the thus-obtained compound of the general formula (I) to a salt thereof. 14. A process for the preparation of the novel compounds of the general formula (I), wherein R 1 , R2, R3 , Q1 , Q2 and π are as defined in claim 13, which comprises transforming an appropriately substituted ketone of the general formula (II), wherein R 1 , R2 , R3 , Q1 and π are as defined in claim 12, with a suitable reactaπt of the general formula (III) H 2 N-NH-R (III) wherein R j_ s as defined in claim 13, to a ketone deriva- tive of the general formula (IV), wherein R 1 , R2 , R3 , R 4, Q1 and n are as defined in claim 13 and cycliziπg the thus-obtained compound of the general formula (IV) by using a suitably selected selenium-containing reagent, preferably selenium dioxide. 15.- A process for the preparation of the compounds of the general formula (IV), wherein R , R , R , R and n are as defined in claim 13 and Q is oxygen, which comprises cycliziπg a compound of the general formula (V) , wherein R , R , R , R and n are as defined in claim 13, by using an acid. 16. A process for the preparation of the novel compounds of the general formula (I), wherein R 1, R2, R3, Q1, Q2 and n are as defined in claim 13, which comprises reacting a compound of the general formula (VI) , wherein R 1, R2, R3, Q1, Q2 and π are as defined in claim 13, with a diazo-transfer reagent in the presence of a base and spontaneously cycliziπg the thus-obtained non-isolated intermediate product. 1 9 - 17. A process for the preparation of the novel compounds of the general formula (I), wherein R 1 , R2, R3, Q1 , Q2 and π are as defined in claim 13, which comprises cycliziπg a compound of the general formula (VII), wherein R 1, R2, R3, Q2 and n are as defined in claim 13, by using an acid, preferably acetic acid. 18. A process for the preparation of the novel compounds of the general formula (I), wherein R 1 , R2, R3, Q1, Q2 and π are as defined in claim 13, which comprises cycliziπg a compound of the general formula (VIII), wherein R 1 , R2, R3, R5 , Q1, Q2 and π are as defined in claim 13, through a non-isolated intermediate by using an alkaline reagent, preferably potassium hydroxide, sodium hydroxide or calcium hydroxide. 19. A process for the preparation of the novel compounds of the general formula (I), wherein R 1 , R7 , R 3 , Q 1 , Q? and π are as defined in claim 13, which comprises reacting a coumariπ derivative of the general formula (IX) , wherein R 3, Q1, Q2 and n are as defined in claim 13, with a Grignard reagent of the general formula R MgX and/or R 2MgX or a metal alkyl, wherein R1 and R2 are as defined In claim 13. 20. A process for the preparation of the compounds of the general formula (X), which comprises cyclizing a ketone derivative of the general formula (IV), wherein one R means a chain connecting two ketones and R , R , R , Q and n are as defined in claim 13, by using an appropriately select¬ ed selenium-containing reagent, preferably selenium dioxide, seleπous acid, selenites or selenium oxychlo¬ ride. 21. A process for the preparation of the novel compounds of the general formula (I), wherein R 1 , R2, R3 , Q1 and π are as defined in claim 13, which comprises cycliziπg a ketone derivative of the general formula (XI), wherein R , R , R , Q and π are as defined in claim 13 and R 4 is for a C=0, C=S, or C=NH group. 22. A process for the preparation of the novel compounds of the general formula (I), wherein R- Q and π'are as defined in claim 13, whereas Q is an SO or S0 2 group, which comprises oxidizing a compound of the general formula (I), wherein Q means a sulfur atom and R ,1 , πR2' 3 , Q2 and n are as defined in claim 13. 23. A process as claimed in claim 13, which comprises cyclizing the compounds of the general formula (IV) by using selenium dioxide. 24. A process as claimed in claim 13, which comprises cycliziπg the compounds of the general for¬ mula (IV) by using seleπous acid. 25. A process as claimed in claim 13, which comprises cyclizing the compounds of the general formula (IV) by using selenites. 26. A process as claimed in claim 13, which comprises cycliziπg the compounds of the general formula (IV) by using selenium oxychloride. 27. A process as claimed in any one of the claims 13, 15, 17, 20, 21, or 23 to 26, which comprises carrying out the cyclizatioπ in a C, . aliphatic carboxy- lic acid, or in a mixture thereof, or in a mixture of such a carboxylic acid and an other solvent. 28. A process as claimed in any one of the claims 13, 20, 21 or 23 to 27, which comprises using the selenium-containing reagent in an amount of 1.0 to 1.5 equivalents. 29. A process as claimed in any one of the claims 13, 20, 21 or 23 to 28, which comprises carrying out the reaction resulting in a cyclization at a tempera¬ ture of 0 to 120 °C, preferably at 20 to 80 °C. 30. A process as claimed in any one of the claims 13, 15, 17, 20, 21 or 23 to 29, which comprises obtaining the compound of the general formula (I) , wherein R 1, R2, R3, Q1, Q2 and n are as defined in claim 13 by evaporation and using repeatedly the thus- -recovered solvent for the cyclizatioπ reaction. 31. A process as claimed in any one of the claims 13 to 29, which comprises obtaining the reaction product by filtration or extraction after pouring into water. 32. A process as claimed in claim 16, which comprises preparing the compounds of the general formula (I), wherein R 1, R2, R3 , Q1, Q2 and n are as defined in claim 13, by using tosyl azide in the presence of triethylamine. 33. A process as claimed in claim 16, which comprises carrying out the cyclizatioπ by using tosyl azide in the presence of trimethylamine. 34. A process as claimed in claim 16, which comprises carrying out the cyclizatioπ by using tosyl azide In the presence of morpholine. 35. A process as claimed in claim 16, which comprises carrying out the cyclization by using tosyl azide in the presence of N-methyl-piperidine. 36. A process as claimed in claim 16, which comprises carrying out the cyclization by using tosyl azide in the presence of piperidine. 37. A process as claimed in claim 16, which comprises carrying out the cyclizatioπ by using tosyl azide in the presence of phenyllithiu . 38. A process as claimed in claim 16, which comprises carrying out the cyclization by using tosyl azide in diethylamine or in the presence of diethyl- amine. 39. A process as claimed in claim 16, which comprises carrying out the cyclizatioπ by using a diazo- -transfer reagent in the presence of an alkaline metal alkoxide. 40. A process as claimed in claim 16, which comprises using an appropriately selected organic nitro¬ gen compounds as a base and/or as solvent. 41. A process as claimed in claim 16, which comprises using a diazo-transfer reagent differing from tosyl azide, preferably 4-azidosulfoπylbeπzoic acid. 42. A process as claimed in any one of the claims 16 or 32 to 39, or 41 which comprises using a C, £ alcohol, acetonitrile, a halogeπated hydrocarbon, aliphatic ether, a cyclic ether, an organic base or an aprotic dipolar liquid as solvent. 43. A process as claimed in any one of the claims 16, or 32 to 42, which comprises carrying out the reaction at a temperature between 0 °C and 120 °C, suitably but not exclusively at 20 to 25 °C. 44. A process for the preparation of a fungi¬ cide, nematocide, acaricide, bactericide and insecticide composition, which comprises mixing as active ingredient a novel compound of the general formula (I), wherein R1 , R2, R3 , Q1, Q2 and n are as defined in claim 13, or a biologically active salt thereof in an amount of 0.001 to 99.5 %, prepared as claimed in any one of the claims 13, 14, 16, to 19, 21 or 22 optionally with other active ingredients and solid and/or liquid carriers, and/or vehicles and/or surface active addi¬ tives, preferably a dispersing, emulsifying or wetting agent and/or other auxiliary materials.

Inventors: BOGNAR REZSOE, DEAK PETER, FODOR ANDRAS, JASZBERENYI CSABA, MAKLEIT SANDOR, TIMAR TIBOR, BOGNAR, REZSOE, DEAK, PETER, FODOR, ANDRAS, JASZBERENYI, CSABA, MAKLEIT, SANDOR, TIMAR, TIBOR
Applicants: ALKALOIDA VEGYESZETI GYAR
Application year: 1987
Main classification: C07D517
IPC codes: A01N43, A01N55, C07D311, C07D513, C07D517, C07F7, C07F9