Dihydropyridazinones and pyridazinones as fungicides

Abstract: This invention relates to substituted dihydropyridazinones, pyridazinones and related compounds, of the formula wherein A is -(CHR²) n -CHR⁷-Z-; -(CHR²) n -O-Z-; -(CHR²) n -S-Z-; -O-CHR⁷-Z-; -CR²=CR⁷-Z-; -CR²=N-Z-; CHR²-CR⁷=Y-; or -CR²=CR²-Y=; D is CR² or nitrogen; Q is Z is carbonyl (C=O) or thiocarbonyl (C=S); Y is carbon substituted with halo, alkoxy, alkynylthio or triazolyl; and either (i) R¹ is alkyl, hydroxyalkyl, cyanoalkyl, hydrazidal and derivatives thereof, cycloalkylalkyl, heterocyclylalkyl, phenyl, phenylalkyl, phenylcarbonyl, alkenyl, haloalkenyl, phenylalkenyl, alkynylalkenyl, alkynyl, haloalkynyl, phenylalkynyl, heterocyclyl, dialkynyl, heterocyclylalkynyl, cycloalkylalkynyl, alkenylalkynyl, hydroxyalkynyl, alkoxyalkynyl, alkanoyloxyalkynyl, formylalkynyl, trialkylsilylalkynyl, trialkyltinalkynyl, haloalkenylalkynyl, carboxyalkynyl, or alkoxy-carbonylalkynyl; R² is hydrogen, (C₁-C₃)alkyl, phenyl, or halogen; R⁷ is hydrogen, (C₁-C₃)alkyl, phenyl, halogen, alkynylalkenyl, alkynyl, dialkynyl, haloalkynyl, or alkenylalkynyl; R³ and R⁶ are independently hydrogen, alkoxy or halogen; R⁴ is hydrogen, halogen, alkoxy or nitro; and R⁵ is hydrogen, halogen, nitro, alkyl, alkoxy, alkylthio, haloalkyl, haloalkoxy, haloalkylthio, phenyl, phenoxy or cyano; or alternatively (ii) R² and R³ together form a (C₁-C₃)alkyl, (C₂-C₃)alkylene or carbonyl link and R¹, R⁴, R⁵, R⁶ and R⁷ are as above; or alternatively (iii) R² and R⁷ together form a fused phenyl ring and R¹, R³, R⁴, R⁵ and R⁶ are as above; and agronomically acceptable salts thereof; compositions containing these compounds and methods of controlling fungal diseases.

Description: This invention concerns substituted dihydropyridazinones, pyridazinones, compositions containing these compounds, and a method of controlling fungi by the use of a fungitoxic amount of these compounds. Although many different types of compounds are known for use as fungicides, and, in particular, for use as agricultural fungicides, there is a continuous demand for new agricultural fungicides. In particular, there is a continuous demand for agricultural fungicides which are active against fungal diseases of rice. Accordingly, one aspect of this invention relates to the use of a class of pyridazinones and dihydropyridazinones and compositions containing them, in the control of agricultural fungal diseases, particularly in rice. US-A-4,738,961 and GB-A-1,533,010 disclose pyridazinones and dihydropyridazinones and their use as fungicides. However, neither of these documents disclose the pyridazinones and dihydropyridazinones of the present invention. Further, although different types of compounds are known for use as human fungicides, there remains a need for additional nontoxic, pathogenically selective compounds useful to control fungal diseases in humans. The compounds of the present invention may be used for pharmaceutical use, particularly for the control of fungal diseases in humans. According to one aspect of the present invention there is provided a compound of the formula (I): wherein R 1 is halo(C 3 -C 6 )alkynyl, (C 3 -C 10 )alkynyl, (C 3 -C 6 )alkenyl (C 3 -C 6 )alkynyl or (C 3 -C 6 )alkynyl(C 3 -C 6 )alkenyl; R 2 is hydrogen or (C 1 -C 6 )alkyl and R 3 is hydrogen, halo or (C 1 -C 6 )alkoxy; or R 2 and R 3 together form a (C 1 -C 3 )alkylene; R 4 is hydrogen, halo or (C 1 -C 6 )alkyl; R 5 is hydrogen, halo or halo(C 1 -C 6 )alkoxy; R 6 is hydrogen or fluoro; and R 7 is hydrogen. and agronomically acceptable salts thereof; provided that, when R 2 , R 3 , R 4 , R 6 and R 7 are hydrogen and R 5 is chloro, R 1 is not CH 2 C=CCH 3 . According to a second aspect of the present invention there is provided a compound of the formula (II) wherein R 1 is (C 3 -C 6 )alkynyl, (C 2 -C 6 )alkynyl(C 3 -C 6 )alkynyl, halo(C 3 -C 6 )alkynyl, (C 2 -C 6 )alkenyl(C 3 -C 6 )alkynyl or tri-((C 1 -C 6 )alkyl)tin(C 3 -C 6 )alkynyl; preferably (C 3 -C 6 )alkynyl; R 2 is hydrogen or halogen, preferably fluoro; and R 3 is hydrogen or (C 1 -C 6 )alkyl; or R 2 and R 3 together form a (C 1 -C 3 )alkylene; and R 4 is hydrogen, halogen or (C 1 -C 6 )alkyl; and R 5 is hydrogen, halogen, (C 1 -C 6 )alkyl, or (C 1 -C 6 )alkoxy; and R 6 is hydrogen or halogen, preferably fluoro; and R 7 is hydrogen or halogen, preferably fluoro, and agronomically acceptable salts thereof. Halo is bromo, fluoro, chloro, and iodo. (C 1 -C 6 )alkyl is straight or branched alkyl, such as methyl, ethyl, n -butyl or t -butyl. (C 3 -C 6 )alkynyl(C 3 -C 6 )alkenyl is, for example, 3-(3-methyl-2-propynyl)-2-propenyl or 3-acetylenyl-2-propenyl. (C 3 -C 10 )alkynyl is, for example, 2-propynyl, 2-butynyl, 1-methyl-2-butynyl, 2-pentynyl, 1-methyl-2-pentynyl, 3-pentynyl, 4-methyl-2-pentynyl, 5,5-dimethyl-2-pentynyl, 2-hexynyl, 2-octynyl or 2-decynyl. (C 3 -C 6 )alkynyl is, for example, 2-propynyl, 2-butynyl, 1-methyl-2-butynyl, 2-pentynyl, 1-methyl-2-pentynyl, 3-pentynyl or 4 methyl-2-pentynyl. Halo(C 3 -C 6 )alkynyl is, for example, 3-iodo-2-propynyl, 4-chloro-2-butynyl, 4-bromo-2-butynyl, 4-fluoro-2-butynyl, 4,4-difluoro-2-butynyl, 5-fluoro-2-pentynyl or 4-fluoro-2-pentynyl. (C 3 -C 6 )alkenyl(C 3 -C 6 )alkynyl is, for example, 3-(vinyl)-2-propynyl, 3-(2-methylvinyl)-2-propynyl or 3-(2-propenyl)-2-propynyl. (C 2 -C 6 )alkenyl(C 3 -C 6 )alkynyl is, for example, 3-vinyl-2-propynyl. Tri(C 1 -C 6 )alkyltin(C 3 -C 6 )alkynyl is, for example, 3-(tri- n -butyltin)-2-propynyl. R 2 and R 3 can be linked together to form a (C 1 -C 3 )alkylene link which can be, for example, a relatively simple linear chain link, such as in 4,4a,5,6-tetrahydro-8-halo[h]-chinolin-2-R 1 -3-one or the 5,6-dihydro form thereof. R 2 and R 3 can be linked together in a (C 2 -C 3 )alkylene link other than a simple linear chain, such as the fused ring structure exemplified by 8-R'-acenaphtho-[1,2c]pyridazin-9-one. In a preferred embodiment of the compounds of formula (I): R 1 is 2-pentynyl, 2-hexynyl, 3-vinyl-2-propynyl, 4-fluoro-2-pentynyl, 5-fluoro-2-pentynyl, or 3-(1-propenyl)-2-propynyl; R 2 is hydrogen; R 3 is hydrogen; or R 2 and R 3 can together form a (C 1 -C 3 )alkylene link; R 4 is hydrogen, methyl, chloro or fluoro; R 5 is chloro, fluoro, bromo or trifluoromethoxy; R 6 is hydrogen or fluoro; and R 7 is hydrogen. Preferably, in this embodiment:- (a) R 1 is 2-pentynyl; and either (i) R 4 is hydrogen, fluoro, chloro or methyl; R 5 is chloro, fluoro, bromo or trifluoromethoxy; and R 6 is hydrogen or fluoro; or (ii) R 2 , R 3 , R 6 and R 7 are hydrogen, R 5 is chloro and R 4 is hydrogen or fluoro; (b) R 1 is 2-pentynyl or 3-vinyl-2-propynyl; R 2 and R 3 are linked together to form a (C 1 -C 3 )alkylene link; R 4 is hydrogen or fluoro; and R 5 is chloro, fluoro or bromo; or (c) R 1 is 2-hexynyl, 3 vinyl-2-propynyl, or 3-(1-propenyl)-2-propynyl; R 4 is hydrogen or fluoro; R 5 is chloro; and R 6 is hydrogen. In a preferred embodiment of the compounds of formula (II): R 1 is 2-pentynyl, 4-fluoro-2-pentynyl, 3-vinyl-2-propynyl, or 5-fluoro-2-pentynyl; R 2 is hydrogen; R 3 is hydrogen; or R 2 and R 3 together form a (C 1 -C 3 )alkylene link; R 4 is hydrogen, fluoro or chloro; R 5 is fluoro, chloro or bromo; R 6 is hydrogen; and R 7 is hydrogen. Preferably, R 1 is 3-vinyl-2-propynyl or 2-pentynyl; and either (i) R 4 is hydrogen or fluoro; and R 5 is chloro, fluoro or bromo or (ii) R 2 , R 3 , R 6 , and R 7 are hydrogen; R 4 is hydrogen or fluoro and R 5 is chloro. More preferably, R 1 is 2-pentynyl or 3-vinyl-2-propynyl; R 2 and R 3 are linked together to form a (C 1 -C 3 )alkylene link; R 4 is hydrogen or fluoro; and R 5 is chloro, fluoro or bromo. In an alternative preferred embodiment of the compounds of formula (II): R 1 is 4-fluro-2-pentynyl or 5-fluoro-2-pentynyl; R 2 and R 3 are each hydrogen or are linked together to form a (C 1 -C 3 )alkylene link; R 4 is hydrogen or fluoro; R 5 is chloro; R 6 is hydrogen; and R 7 is hydrogen. Compound 1 in Table 1 below, which is useful in the method of the present invention is known and commercially available. However, it has not previously been disclosed to be active against Pyricularia oryzae and thus it has not been disclosed to be active in the method of the present invention. The dihydropyridazinones compounds of the present invention are prepared, for example, by a two-step sequence starting from an arylketo acid or ester of the formula wherein Q is as defined in Formula I above and R a is hydrogen or alkyl. Compound III is reacted with about an equivalent of hydrazine or a substituted hydrazine having the formula H 2 NNHR b wherein R b is hydrogen to yield a compound having the formula Examples of suitable solvents for this reaction include alcohols, such as ethanol, n-propanol or n-butanol. The reaction is generally carried out at about atmospheric pressure at a temperature of from -10°C to 200°C. Preferably, the temperature employed is in the range of from 25°C to 150°C, more preferably from 50°C to 125°C. The compound of Formula V wherein R b is hydrogen is then alkylated using the appropriate alkylating agent, for example an alkynyl mesylate or alkynyl halide, by a standard N-alkylation procedure, for example, using sodium hydride in an aprotic polar solvent such as dimethylformamide (DMF) or by using a phase transfer catalyst such as tetrabutylammonium hydrogen sulfate to obtain the desired dihydropyridazinone (formula V wherein R b is not hydrogen) of the present invention. The reaction is generally carried out at a temperature of from -10°C to 250°C. More preferably, the reaction is carried out at a temperature of from 20°C to 100°C. The dihydropyridazinone of Formula V wherein R b is hydrogen can be converted to the corresponding pyridazinone of the invention, for example, by bromine oxidation. The reaction is generally carried out in an organic acid solvent such as acetic acid at a temperature of from 0°C to 150°C. More preferably, the temperature ranges from 20°C to 100°C, more particularly from 50°C to 75°C. The starting arylketoacids can be obtained from commercial sources or prepared by procedures known in the literature such as 1) Friedel-Crafts acylation of aromatic compounds with succinic anhydride, 2) a malonic ester condensation (the preparation of bis-(di-t-butyl-carboxy)ethylcarboxyethane from di-t-butylmalonate, acylation with an aromatic acyl chloride and decarboxylation of the ketotriester) or 3) a Claisen condensation. Typically, the alkynyl mesylates and alkynyl halides used in the alkylation step of the procedure are prepared by means known in the art, for example: a) from commercially available alcohols b) from commercially available alkynes wherein R 7 is alkyl, etc. and R is, for example, alkyl. Additionally, the alkynyl group can be modified after the alkylation step has taken place, for example by treatment with a haloalkene in the presence of bis(triphenylphosphine)palladium dichloride, copper(I) iodide and triethylamine to add an alkenyl group to the alpha carbon of the alkyne: Alternatively, the alkynyl halide, used in the alkylation of the compound of formula V wherein R 6 is hydrogen, may be obtained form propargyl chloride: wherein R is, for example, alkyl, and the alkynyl group in the resulting dihydropyridazinone can be modified, for example, by treatment with diethylaminosulfur trifluoride (DAST) to add fluorine to the carbon alpha to the alkynyl: The pyridinones are prepared, for example, by cyclization of 2-aryldialkylamino propenals (VI) and a cyanoacetamide (VII) in the presence of base to yield the corresponding 3-cyano-5-aryl-pyridinone (VIII), which is then hydrolyzed and decarboxylated to yield the pyridinone (IX). The pyridinone is alkylated as described above for the dihydropyridazinones to yield compounds of the invention. Examples of suitable solvents for the cyclization reaction include alcohols, such as methanol or ethanol. Examples of suitable bases include sodium methoxide and sodium ethoxide. The reaction is generally carried out at about atmospheric pressure at a temperature of from 25°C to 250°C. Preferably, the temperature employed is in the range of from 50°C to 200°C, more preferably from 100°C to 150°C. The hydrolysis and decarboxylation step is typically carried out in a strong acid such as 85% H 3 PO 4 or concentrated sulfuric acid at atmospheric pressure at temperatures between 50 and 200°C, preferably between 100-150°C. The starting indenopyridazinones (X), wherein R 8 is hydrogen or (C 1 -C 2 )alkyl, can be prepared by carboxymethylating the appropriate indanone (XI) using an agent such as dimethylcarbonate in the presence of base such as sodium hydride and an aprotic solvent such as dimethoxyethane, followed by alkylation with an agent such as ethyl bromoacetate in the presence of base such as sodium hydride and an aprotic solvent such as dimethylformamide to obtain the diester (XII). The diester is subsequently decarboxylated and hydrolyzed using standard procedures, preferably heating in a aqueous acid solution, more preferably, refluxing in aqueous hydrochloric acid to obtain the corresponding ketoacid (XIII) which is cyclized and alkylated as described above for the dihydropyridazinones to yield compounds of the present invention. The following examples will further illustrate this invention, but are not intended to limit it in any way. In Tables I to III examples of compounds of the invention are listed. In Tables I and IV compounds 47, 69 and 88 are not compounds of the present invention. For compounds that are new, elemental analyses are listed in Table IV or proton NMR data is listed in Table V. Specific illustrative preparations of the compounds are described after Table V. ELEMENTAL ANALYSES Cmpd Calculated Found No. %C %H %N %C %H %N 6. 63.39 4.49 11.35 66.22 5.66 8.92 12. 65.57 5.50 10.19 65.34 5.63 9.43 13. 68.87 5.41 11.50 68.63 5.29 11.24 19. 56.96 4.10 9.49 56.97 4.60 8.70 21. 65.57 5.50 10.20 65.29 5.30 10.36 22. 65.57 5.50 10.20 65.25 5.22 10.16 23. 56.95 4.07 9.45 57.19 4.18 9.16 24. 77.92 7.79 9.09 75.12 7.67 8.85 26. 65.57 5.50 10.20 63.70 5.47 9.68 28. 58.27 4.56 9.06 58.58 4.55 8.82 29. 66.51 5.96 9.71 67.73 6.57 8.77 31. 55.00 4.26 9.18 57.92 5.39 8.05 34. 66.54 5.93 9.70 66.36 5.89 9.59 37. 64.50 5.02 10.74 64.06 4.93 10.60 45. 67.01 5.27 9.76 67.32 5.37 8.94 46. 67.43 6.32 9.25 67.26 6.52 9.19 47. 61.96 5.20 9.63 61.93 5.56 8.67 60. 41.88 2.68 7.52 32.86 2.39 6.25 63. 65.57 5.46 10.20 67.67 6.35 9.11 69. 47.66 3.69 8.55 48.89 3.89 8.33 70. 68.67 6.08 8.89 63.30 5.56 8.03 71. 49.51 3.56 8.24 48.20 3.35 7.50 72. 56.96 4.10 9.49 54.00 3.89 8.53 73. 61.54 4.79 9.57 63.47 5.59 8.54 76. 60.33 4.34 10.00 59.18 4.13 9.61 82. 69.75 5.85 10.85 70.53 6.22 10.09 85. 69.65 7.30 8.12 69.77 7.26 8.04 88. 61.21 4.03 10.19 60.73 4.06 9.70 89. 56.67 3.74 9.44 55.02 3.77 8.80 91. 56.44 4.80 8.78 58.76 5.39 7.55 96. 68.23 6.68 8.84 67.96 6.48 8.63 108. 64.99 4.26 10.83 64.72 4.17 10.68 109. 62.83 4.54 9.77 65.73 4.82 10.21 110. 76.79 6.77 10.53 75.75 6.92 9.50 111. 77.55 7.48 9.52 72.95 7.68 7.66 112. 58.63 3.91 9.12 58.44 4.04 8.97 113. 67.02 5.24 9.77 69.13 6.38 8.21 114. 66.06 4.77 10.28 64.29 5.04 9.92 115. 67.02 5.24 9.77 66.91 5.30 9.77 116. 66.09 4.77 10.28 65.85 4.94 9.99 117. 72.36 6.43 9.92 66.42 5.51 6.52 118. 63.81 3.70 11.45 63.81 3.62 11.39 119. 66.55 4.09 10.34 64.70 3.84 10.13 128. 62.40 3.49 7.70 62.36 3.29 9.51 143. 67.01 5.27 9.76 64.82 4.99 9.72 145. 70.72 5.16 5.16 69.34 5.21 4.86 155. 67.88 5.70 9.31 68.06 5.50 8.83 NMR DATA Ex. No. Solvent (200 MHz, delta scale in ppm, Tetramethylsilane (TMS) standard) 9. CDCl 3 1.9(s,3H); 2.6(t,2H); 3.0(t,2H); 4.6(s,2H); 7.4(m,3H); 7.8(m,2H) 51. CDCl 3 2.5(t,2H); 2.65(t,2H); 2.95(t,2H); 3.69(m,1H); 4.4(m,1H); 4.6(s,2H); 7.75(d,2H) 53. CDCl 3 1.6(dd,3H); 265(t,2H); 2.95(t,2H); 4.7(s,2H); 5.75(m,1H); 7.4(d,2H); 7.75(d,2H) 62. CDCl 3 1.1(t,3H); 2.2(q,2H); 2.4(s,3H); 2.6(t.3H); 2.95(t,3H); 4.6(s,2H); 7.4(d,1H); 7.55(d,1H); 7.7(s,1H) 74. CDC13 1.1(t,H3); 2.2(q,2H); 2.5(t,2H); 2.95(t,2H); 4.55(s,2H); 7.3-7.7(m,3H) 90. CDCl 3 1.1(t,3H); 2.2(q,2H); 2.6(t,2H); 3.0(t,2H); 4.6(s,2H); 7.4(d,2H) 92. CDCl 3 1.1(t,3H); 2.15(q,2H); 2.6(t,2H); 2.95(t,2H); 4.6(s,2H); 6.6(t,lH); 7.3(t,lH); 7.5(d,1H); 7.7(d,1H) 97. CDCl 3 1.1(t,3H); 2.2(q,2H); 2.6(t,2H); 2.95(t,2H); 4.5(s,2H); 7.4-7.8(m,3H) 98. CDCl 3 1.1(t,3H); 2.2(q,2H); 2.65(t,2H), 2.95(s,2H); 4.5(s,2H); 6.8-7.3(m,3H) 99. CDCl 3 1.1(t,3H); 2.2(q,2H); 2.5(t,2H); 2.9(t,2H); 3.9(s,3H); 4.6(s,2H); 7.0(d,2H); 7.45(d,2H) 101. CDCl 3 1.8(dd3H); 2.6(t,2H); 2.9(t,2H); 4.8(d,2H); 5.5(m,1H); 6.1(m,1H); 7.4(d,2H); 7.7(d,2H) 102. CDCl 3 1.9(d,3H); 2.6(t,2H); 2.9(t,2H); 4.8(s,2H); 5.5(d,1H); 6.0(m,1H); 7.4(d,2H); 7.7(d,2H) 103. CDCl 3 1.8(d,3); 2.6(t,2); 2.9(t,2); 4.7(s,2); 5.5(d,2); 6.2(m,1);7A(d,2); 7.7(d,2) 104. acetone-d 6 1.1(t,3H); 2.1(q,2H); 2.65(t,2H); 3.0(t,2H); 4.5(s,2H); 7.2-7.8(m,3H) 115. CDCl 3 1.0(t,2H); 1.2(t,2H); 1.5(t,2H); 2.2(m,3H); 3.0(m,3H); 4.2(q,3H); 6.0(m,2H); 7-7.6(m,4H) 120. CDCl 3 1.1(t,3H); 2.2(q,2H); 5.0(s,2H); 7.05(d,lH); 7.5(d,1H); 7.55(s,1H); 7.6(d,1H); 7.65(d,1H) 121. CDCl 3 1.1(t,3H); 2.2(q,2H); 4.95(s,2H); 7.05(d,1H); 7.5-7.8(m,5H) 122. CDCl 3 1.2(t,3H); 2.2(q,2H); 5.0(s,2H); 7.5(d,2H); 7.8(d,2H) 123. CDCl 3 1.1(t,3H); 2.2(m,2H); 4.9(s,2H); 7.1(s,1H); 7.4(d,2H); 7.8(d,2H) 124. CDCl 3 0.9(t,9H); 1.0(q,6H); 1.2(q,6H); 1.5(q,6H); 5.0(s,2H); 7.0(d,1H); 7.4(d,2H); 7.7(d,2H) 7.8(d,2H) 126. CDCl 3 1.1(t,3H); 2.2(q,2H); 5.0(s,2H); 6.8-7.0(m,1H); 7.37.5(m,2H); 7.7(d,1H) 127. acetone-d 6 1.1(t,3H), 2.2(q,2H), 4.9(s,2H), 7.0(d,1H), 7.7-7.9(m,3H), 8.1(d,1H) 129. CDCl 3 1.1(t,3H); 2.2(q,2H); 5.0(s,2H); 7.0(d,1H); 7.25(t,1H); 7.7(dd, 2H); 8.0(d,1H) 130. CDCl 3 1.6(dd,3H), 5.1(m,2H), 5.15(m,1/2H), 5.4(m,1/2H), 7.1(d,1H), 7.5(d,2H), 7.7(d,1H), 7.8(d,2H) 131. CDCl 3 2.65(m,2H), 4.4(t,1H), 4.6(t,1H), 5(m,2H), 7.0(d,1H), 7.5(d,2H), 7.7(d,1H), 7.8(d,2H) 200. CDCl 3 1.1(t,3H); 1.6(m,1H); 2.2(m,3H); 2.8(m,3H); 4.6(t,2H);7.2(m,2H); 8.1(d,1H) 202. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.9(s,4H); 4.9(t,2H); 6.8(s,1H); 7.3(m,2H); 8.0(d,1H) 208. CDCl 3 1.1(t,3H); 1.5(d,1H) 2.2(m,2H); 2.6(t,2H); 2.9(t,2H); 5.7(m,1H); 7.4(d,2H); 7.8(d,2H) 209. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.6(t,2H); 3.0(t,2H); 4.6(m,2H); 7.2(m,2H); 7.4(m,1H); 7.8(m,1H) 211. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.6(t,2H); 2.9(t,2H); 4.6(m,2H); 7.4(m,4H) 212. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.5(t,2H); 2.9(t,2H); 3.8(s,3H); 4.6(m,2H); 7.0(m,2H); 7.4(m,1H); 7.6(m,1H) 214. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.6(t,2H); 2.9(t,2H); 4.6(m,2H); 7.1(m,1H); 7.4(m,1H); 7.6(m,2H) 215. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.4(s,3H); 2.6(t,2H); 2.9(t,2H); 4.6(m,2H); 7.3(m,2H); 7.6(m,2H) 216. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.6(t,2H); 3.0(t,2H); 4.6(m,2H); 7.4(m,2H); 7.7(m,lH); 7.9(s,2H) 222. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.6(t,2H); 2.9(t,2H); 4.6(m,2H); 4.6(m,2H); 7.2(t,1H); 7.7(m,1H); 8.1(dd,1H) 224. CDCl 3 1.1(t,3H); 2.2(m,2H); 2.6(t,2H); 2.9(t,2H); 4.6(m,2H); 7.2(q,1H); 7.5(m,1H); 7.7(m,1H) EXAMPLES In the following Examples, Examples 11, 47, 54, 56, 69 and 88 produce compounds not in accordance with the present invention. Example 6: 6-(4-chlorophenyl)-2-propargyl-4,5-dihydropyridazinone a. 6-(4-chlorophenyl)-4,5-dihydropyridazinone To a mixture of 10 g of 3-(4-chlorobenzoyl)propionic acid and 100 ml of ethanol, 2.4 g of hydrazine monohydrate was added portionwise with stirring and the reaction was refluxed for 2 hours. Upon cooling a white crystalline solid was formed which was filtered off and dried to yield 9.7 g (99%) of the dihydropyridazinone. b. 6-(4-chlorophenyl)-2-propargyl-4,5-dihydropyridazinone A mixture of 0.17 g of sodium hydride (60% in oil) and 50 ml of dry dimethylformamide (DMF) was cooled to 5°C and 0.8 g of the dihydropyridazinone from part a in 25 ml of dry DMF was added dropwise. The reaction was warmed to room temperature for 30 minutes and then cooled to 5°C. Propargyl chloride (0.31 g) was added dropwise and the reaction was stirred overnight at ambient temperature. The reaction was quenched with 100 ml of water and extracted with ethyl ether (3x100 ml). The organic fractions were combined, washed with water (2x100 ml) and saturated brine (1x100 ml). The ether extract was then dried over anhydrous magnesium sulfate, filtered, and evaporated in vacuo to yield 0.68 g (91%) of compound 6 as a tan solid. Compounds 9, 13, 19, 69, 71 and 142 were prepared following essentially the same procedure as described in Example 6b and using the appropriate starting dihydropyridazinone and substituting for propargyl chloride the appropriate alkyl halide chosen from bromobutyne, 1,3-dibromo-1-propene, or 1,4-dibromo-2-butyne or a mesylate such as 2-butyn-1-yl-methanesulfonate. Example 11: 6-(4-methoxyphenyl)-2-(2'-butynyl)-4,5-dihydropyridazinone a. 2-butyn-1-yl-methanesulfonate To a solution of 25 g of 2-butyn-1-ol in 200 ml of anhydrous diethyl ether, 72 g of triethylamine was added in one portion and the reaction mixture was cooled to 0°C. Methanesulfonyl chloride (40.8 g) was added dropwise maintaining the temperature below 5°C. Then the reaction was stirred for 2 hours at 0-5°C and the triethylamine salts were filtered off and washed with 100 ml of ether. The ether fractions were combined, washed with water (100 ml), brine (100 ml), dried over magnesium sulfate and evaporated in vacuo to yield 39.6 g of the mesylate as a yellow liquid. b. 6-(4-methoxyphenyl)-2-(2'-butynyl)-4,5-dihydropyridazinone The starting 6-(4-methoxyphenyl)-4,5-dihydropyridazinone was prepared following essentially the procedure described in Example 6a and alkylated with the mesylate from 11a following essentially the procedure described in 6b. Compounds 21, 29 and 85 were prepared following essentially the same procedure, using the appropriate substituted dihydropyridazinone and preparing the appropriate mesylate using the appropriate alcohol chosen from 3-pentyn-1-ol, 2-hexyn-1-ol, and 2-decyn-1-ol. Example 12: 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone a. ethyl 3-bis(di-t-butylcarboxy)propionate To a solution of 12.5g (0.11 mole) of potassium t- butoxide in 120 ml of t-butanol was added 20 g of di-t-butylmalonate dropwise at room temperature. A solid paste was formed that made stirring difficult. After 15 minutes at room temperature 16.7g of ethyl bromoacetate was added dropwise and the resulting mixture stirred at room temperature overnight. The alcohol was removed in vacuo, the residue was taken up in 150 ml of water and the resulting mixture extracted with ether (3x80 ml). The combined ether layers were dried (magnesium sulfate, (MgSO 4 )) and evaporated. The residue was distilled through a short Vigreux column. The fractions boiling at 125-135°C/l mm were collected to yield 14.2 g (51%) of the triester as a clear oil. b. ethyl 3-(4-chlorophenyl)-bis(di-t-butylcarboxy)propionate Sodium hydride (60% in mineral oil, 240 mg, 5 mmoles) was suspended in dry dimethylformamide (DMF) (20 ml) and cooled to 0°C. To the resulting mixture was added ethyl 3-bis(di-t-butylcarboxy)-propionate (1.51g, 5 mmoles) dropwise. After 10 minutes at 0°C 4-chlorobenzoyl chloride (0.88g, 5 mmoles) was added dropwise and the resulting suspension was stirred at 0°C during 1/2 hour. The reaction mixture was poured into saturated aqueous ammonium chloride (100 ml) and extracted with ether (3x80 ml), the combined organic layers were washed with brine (3x100 ml), dried and evaporated to yield ethyl 3-(4-chlorophenyl)-3-bis(di-t-butylcarboxy)propionate. c. 3-(4-chlorobenzoyl)propionic acid The compound obtained in part b was dissolved in 50 ml of toluene and 100 mg of p-toluenesulfonic acid was added and the resulting solution was heated 80-85°C overnight. After cooling at room temperature, the reaction mixture was extracted with 2% aqueous sodium bicarbonate, dried and evaporated to yield 3-(4-chlorobenzoyl)-propionic acid. d. 6-(4-chloropheny)-4,5-dihydropyridazinone To a solution of 3-(4-chlorobenzoyl)propionic acid (20g) in absolute ethanol (200 ml) was added 5 g of hydrazine monohydrate. A thick solid was formed which dissolved after heating. The resulting solution was refluxed for 3 h, cooled and the solid formed filtered and dried to yield 16 g (80%) of 6-(4-chlorophenyl)-4,5-dihydropyridazinone. e. 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone Method i To a suspension of sodium hydride (NaH) (210 mg 60% in mineral oil) in dry DMF at 0°C was added 6-(4-chlorophenyl)-4,5-dihydropyridazinone (1.0 g) in DMF (30 ml) dropwise. The yellow mixture was stirred at 0°C until gas evolution ceased. To the mixture was added 1-bromopent-2-yne (0.8 g) at 0°C and kept at that temperature for 1/2 h. The reaction mixture was poured into saturated aqueous ammonium chloride (100 ml) and extracted with ether (3x100 ml). The combined organic layers were washed with brine (2x50 ml), dried and evaporated. Trituration of the oily residue with hexane yielded the product as a light yellow solid. Method ii To a stirred mixture of 1-bromopent-2-yne (1.4 g), 6-(4-chlorophenyl)-4,5-dihydropyridazinone (1.0 g), toluene (150 ml) and tetrabutylammonium hydrogen sulfate (100 mg) was added 50% aqueous NaOH (1.9 g) added dropwise. The reaction mixture was heated with continuous stirring at 50°C for 4 h. The reaction mixture was cooled to room temperature and the layers separated. The organic layer was washed several times with water, dried and evaporated to yield 1.2 g (91%) of 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone as a white solid. Using the same procedure as described for this example compounds 60, 62, 63, 73, 82, 90, 91, 96-99, 103 and 104 were made starting from the appropriate benzoyl chloride and alkylating with the appropriate alkyl halide or mesylate. Example 26: 6-(4-chlorophenyl)-5-methyl-2-(2'-butynyl)-4,5-dihydropyridazinone a. 2-methyl-3-(4-chlorobenzoyl)propionic acid To a mixture of 11.4 g of methyl succinic anhydride and 38.7 g of chlorobenzene, 30 g of aluminum chloride was added below 35°C. Then the reaction mixture was warmed to 60-70°C for 2 hours, cooled and cautiously poured onto 500 g of ice. The mixture was extracted with ether (4x100 ml). The organic layers were combined, washed with water (2x100 ml) and brine (2x100 ml), then dried over magnesium sulfate and evaporated in vacuo to yield a viscous oil which crystallized on standing. The solid was filtered off to yield 12.1 g of 1-methyl-3-(4-chlorobenzoyl)propionic acid. The remainder of the noncrystalline material was identified as 2-methyl-3-(4-chlorobenzoyl)propionic acid. b. 6-(4-chlorophenyl)-5-methyl-2-(2'-butynyl)-4,5-dihydropyridazinone The 1-methyl-3-(4-chlorobenzoyl)propionic acid from part a was reacted essentially as described in Example 6 to yield Compound 26. Example 28: 6-(3,4-dichlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone a. 3,4-dichlorobenzoylpropionic acid To a mixture of 1,2-dichlorobenzene (29.4 g) and succinic anhydride (10 g) was added anhydrous aluminum chloride (28.0 g) portionwise with stirring at room temperature. The resulting mixture was heated at 80°C for 6 hours, cooled to room temperature and poured into ice-water (600 g). The aqueous suspension was extracted with ethyl ether (4x150 ml), the combined organic layers were washed with water (2x150 ml), dried and evaporated. The oily-solid residue was triturated with hexane-ether (8:2) yielding the product as a yellow solid. b. 6-(3,4-dichlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The 3,4-dichlorobenzoylpropionic acid was converted to the desired product using essentially the same procedures as described in Example 12d,e. Compound 23 was made from the appropriate starting material using essentially the same procedure. Example 34: 6-(4-chlorophenyl)-2-(3'-methyl-2'-butynyl)-4,5-dihydropyridazinone a. 3-methyl-2-butyn-1-ol A solution of 3-methyl-1-butyne in 200 ml of dry THF was cooled to -78°C and n-butyl lithium (0.160 mole) was added dropwise below 60°C. After stirring for 1 hour at -78°C, gaseous formaldehyde was introduced into the reaction by heating paraformaldehyde (7 g) to a melt and applying a positive pressure to the system to create a formaldehyde atmosphere. The reaction mixture was stirred for 1 hour and then allowed to warm to room temperature and quenched with 100 ml saturated ammonium chloride solution and extracted with ether (3x100 ml). The organic layers were combined, washed with brine (3x100 ml), dried over magnesium sulfate and evaporated in vacuo to yield 3-methyl-2-butyn-1-ol in 60% yield. b. 6-(4-chlorophenyl)-2-(3'-methyl-2'-butynyl)-4,5-dihydropyridazinone The alcohol was mesylated using essentially the procedure described in Example 11a and alkylated using essentially the procedure described in Example 6b to yield 1.1 g of Compound 34. Compounds 45 and 46 were prepared following essentially the same procedure using isopropyl acetylene or 3,3-dimethyl-1-butyne in place of 2-methyl-1-butyne in part a. Example 37: 6-(3-chlorophenyl)-2-(2'-butynyl)-4,5-dihydropyridazinone a. 3-(3-chlorobenzoyl)propionic acid Sodium (11 g, spheres) was added to 200 ml ethanol with stirring. When the gas evolution ceased, methyl 3-chlorobenzoate (10 g, 0.057 mole) and dimethyl succinate (9.0 g, 0.615 mole) were added rapidly and the mixture was stirred for 5 minutes at room temperature. The mixture was slowly concentrated on a rotary evaporator to yield a greenish paste which was slurried in 100 ml ether and an additional 2 ml of dimethyl succinate was added. The reaction was evaporated to a paste, quenched with water and extracted with ether. The ether extracts were washed with water and brine, dried and evaporated in vacuo. The starting material was distilled from the residue and the remaining material was refluxed in 6N hydrochloric acid for 2 days to yield 1.6 g of the desired ketoacid which was filtered off. b. 6-(3-chlorophenyl)-2-(2'-butynyl)-4,5-dinydropyridazinone The ketoacid from part a was reacted essentially as described in Example 6a and b to yield 0.75 g of compound 37 as a tan solid. Example 47: 6-(4-chlorophenyl)-2-(4'hydroxy-2'-pentynyl)-4,5-dihydropyridazinone a. 2-hydroxy-5-iodo-3-pentyne Propargyl chloride was hydroxyethylated with acetaldehyde and n-butyl lithium as described in Example 34a. A solution of 2-hydroxy-5-chloro-3-pentyne (2.0g) and anhydrous sodium iodide (12.6g) in 100 ml of dry acetone was stirred overnight at room temperature. The acetone was evaporated in vacuo and the residue was extracted with ether (2x100 ml). The ether extracts were washed with water (2x100 ml) and brine (100 ml), dried and evaporated in vacuo to yield the iodide as a red liquid. b. 6-(4-chlorophenyl)-2-(4'hydroxy-2'-pentynyl)-4,5-dihydropyridazinone The iodide was used essentially as described in Example 6b, except that 2 equivalents of sodium hydride were used and the reaction mixture was acidified to pH 5 before extraction to obtain the desired product. Example 51: 6-(4-chlorophenyl)-2-(5'-fluoro-2'-pentynyl)-4,5-dihydropyridazinone A solution of 120 milligrams of compound 50 and 50 ml of methylene chloride was cooled to 0°C and a solution of 130 mg of diethylaminosulfur trifluoride (DAST) in 15 ml of methylene chloride was added dropwise. The reaction mixture was stirred at 0-5°C for 1 hour and overnight at room temperature, then quenched with 100 ml of brine and extracted with methylene chloride (2x100 ml). The combined organic extracts were washed with brine (100 ml) and evaporated to yield a yellowish oil which was chromatographed on 50 g of silica (50/50 ethyl acetate/hexane) to yield 60 milligrams of compound 51. Following essentially the same procedure, compounds 53 and 89 were prepared starting from compounds 47 and 88. Example 54: 6-(4-chlorophenyl)-2-(3-'carboxy-2'-propynyl)-4,5-dihydropyridazinone a.. 3-carboxypropargyl chloride A solution of 10g of propargyl chloride in 200 ml of dry ether was cooled to -70°C and 100 ml of methyllithium (1.4 molar solution in hexane) was added dropwise in 30 minutes. The reaction mixture was stirred under a carbon dioxide atmosphere for 45 minutes at -60°C, then slowly warmed to room temperature, quenched with 100 ml of brine, acidified to pH 5 and extracted with ether (3x100 ml). The ether layers were combined, washed with 100 ml of water, 100 ml of brine, dried over magnesium sulfate and evaporated to yield a dark brown liquid which was fractionally distilled (0.4 mm Hg, 187-190°C) to yield 2.6 g of the acid. b. 6-(4-chlorophenyl)-2-(3'-carboxy-2'-propynyl)-4,5-dihydropyridazinone The acid from part a was used following essentially the procedure described for compound 47 to obtain compound 54 as a tan solid. Example 56: 6-(4-chlorophenyl)-2-(3'-vinyl-2'-propynyl)-4,5-dihydropyridazinone A solution of 1.0 g of compound 6, 0.62 g of vinyl iodide and 100 ml of triethylamine was degassed with nitrogen and 50 milligrams each of copper(I)iodide and bis-triphenylphosphine palladium dichloride was added. After stirring overnight at 50°C, the triethylamine was evaporated and the residue was redissolved in 150 ml of ether, passed through 10 g of silica and evaporated to yield 1.0 g of compound 56 as a yellow oil. Compound 119, was prepared following essentially the same procedure using the appropriate starting material. Compound 70 was prepared from compound 69 and 3-methylbutyne following essentially the same procedure. Example 72: 6-(4-chlorophenyl)-2-(4'-chloro-2'-butynyl)-4,5-dihydropyridazinone To a solution of 2.5 g of 6-(4-chlorophenyl)-4,5-dihydropyridazinone in 100 ml of toluene there was added 100 milligrams of tetrabutylammonium hydrogen sulfate and with rapid stirring added 4 7 g of 50% aqueous sodium hydroxide. Then 1,4-dichloro-2-butyne (7.4 g) in 50 ml of toluene was added dropwise and the reaction mixture was heated to 50-60°C for 4 hours. The reaction mixture was cooled and poured into 200 ml of water. The organic phase was separated and the aqueous phase was extracted with ether (2x100 ml). The combined organic phases were washed with 100 ml of water, 100 ml of brine and dried over magnesium sulfate and evaporated to yield a crude product which was chromatographed to yield 1.9 g of compound 72. Compound 128 was prepared following essentially the same procedure starting with 6-(4-chloro-3-fluorophenyl) pyridazinone and using powdered potassium hydroxide instead of sodium hydroxide. Example 74: 6-(4-chloro-3-fluorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone Method A a. 4-chloro-3-fluorobenzoic acid Method i 0.7 Gram-atom (17.0 g) of magnesium turnings was covered with 100 ml of dry ethyl ether and 0.05 mole (0.95g) of 1,2-dibromoethane was added down the side of the flask in such a way that it did not mix with the ether but contacted the magnesium. The mixture was allowed to stand without stirring until bubbles formed around the turnings and the ether became cloudy. Then the mixture was stirred and warmed to mild reflux and 0.62 mole (130.0 g) of 4-chloro-3-fluorobromobenzene in 500 ml of dry ether was added to the flask at such a rate that there was a mild reflux. The refluxing and stirring were continued for 30 minutes after the addition of the halide was completed. The reaction mixture was then cooled to -10°C and dry CO 2 was bubbled in below -2°C. The reaction was complete when the temperature fell below -10°C and did not rise when increasing the rate of flow of CO 2 . To the cold mixture was added 150 ml of 25% HCI at 0°C. The layers were separated and the aqueous layer was washed with ether (3x150 ml). The combined organic layers were washed with water (2x200 ml), dried and evaporated to yield the product as a white solid. 98 g (91% yield). Method ii A mixture of 110g of 98% H 2 SO 4 and 192 g (0.97 mole) of 4-chloro-3-fluorobenzotrifluoride was stirred and then heated cautiously until the hydrogen fluoride evolution started (approx. 130°C). The reaction mixture was heated at 130-135°C for 17 hours, and poured into 1 Kg of ice. The resulting white precipitate was filtered off and washed with water until the pH of the washing liquids was neutral, and the precipitate was dried to yield 165 g (98%) of the expected acid as a white solid. b. 6-(4-chloro-3-fluorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The 4-chloro-3-fluorobenzoic acid was then converted to the corresponding acid chloride by standard means. The desired product was produced following essentially the procedures of Example 12b-e. Method B a. 4-chloro-3-fluorobenzoylpropionic acid To a solution of succinic anhydride (6.0 g) in tetrahydrofuran (60 ml) was added dropwise the Grignard prepared from 1.5g (0.062 mole) of magnesium turnings and 10.5g (0.05 mole) of 1-bromo-4-chloro-3-fluorobenzene using the procedure of part a. When the addition was completed, the resulting suspension was stirred for 2 hours at 45°C after which water (100 ml) was added slowly and the resulting mixture was acidified with concentrated hydrochloric acid to pH=1. The ether layer was separated and extracted with 5% aqueous sodium hydroxide (3x 100ml). The combined aqueous solutions were washed with ether (1x 100ml). The combined basic aqueous layers were acidified with concentrated hydrochloric acid to pH 1 and extracted with ethyl acetate (3x 150ml). The combined organic extracts were washed with water (1x 150ml) and brine (1x 150ml), dried over anhydrous magnesium sulfate and evaporated in vacuo to give 7.1g (62%) of the product as a yellow orange solid. The resulting acid was converted to the desired product using the procedure of Example 12d-e. Compound 83 was prepared following essentially the same procedure. Example 76: 6-(4-chlorophenyl)-2-(4'-fluoro-2'-butynyl)-4,5-dihydropyridazinone a. 4-tetrahydropyranoxy-2-butyn-1-ol To a mixture of 5.0 g of 2-butyne-1,4-diol and 10 milligrams of p -toluenesulfonic acid and 150ml of dry ether there was added dropwise with stirring at room temperature 4.9 g of 3,4-dihydro-2H-pyran. After stirring overnight at ambient temperature the ether was evaporated and the residue was poured into 200 ml of water. The aqueous solution was extracted with hexane (2x100 ml) and then re-extracted with ether (3x100 ml). The combined ether extracts were washed with 100 ml of brine, dried over magnesium sulfate and evaporated to yield 6.8 g of 4-tetrahydropyranoxy-2-butyn-1-ol. b. 6-(4-chlorophenyl)-2-(4'-hydroxy-2'-butynyl)-4,5-dihydropyridazinone The alcohol was converted to the mesylate using essentially the procedure described in Example 11a and the mesylate was used in the alkylation following essentially the procedure describe in Example 6b. The resulting compound was dissolved in 100 ml of methanol. Amberlite IR20 (2 g) resin was washed with 10 ml of methanol and added to the reaction mixture. After stirring for 1 hour, the resin was filtered off and the methanol was evaporated. The oily residue was triturated with hexane to yield 1.3 g of the desired alcohol as a tan solid. c. 6-(4-chlorophenyl)-2-(4'-fluoro-2'-butynyl)-4,5-dihydropyridazinone The alcohol from part b was treated with DAST following essentially the procedure described in Example 51. Silica gel chromatography (50:50 hexane/ethyl acetate) of the crude product yielded 300 milligrams of compound 76 as a pale yellow solid. Example 86: chlorophenyl)-2-(4'-trimethylsilyl-2'-butynyl)-4,5-dihydropyridazinone The bromide of trimethylsilyl propargyl alcohol was prepared following essentially the procedures described in Examples 11a and 33a. To a mixture of 300 ml of dry tetrahydrofuran and 4.8 g of sodium hydride (60% in oil) there was added 25 g of 6-(4-chlorophenyl)-4,5-dihydropyridazinone dissolved in 200 ml of tetrahydrofuran. When the hydrogen gas evolution stopped, the solvent was removed in vacuo. The resulting solid was slurried in hexane and filtered off to yield 27.4 g of the sodium salt as a white non-hydroscopic solid. A solution of 1.0 g of the sodium salt in 50 ml of dimethylformamide was cooled to 5°C and 0.9 g of 1-bromo-3-trimethylsilyl-2-propyne was added dropwise. After stirring for 30 minutes at 5°C, the reaction mixture was warmed to room temperature, quenched with 100 ml of water and extracted with ether (3x100 ml). The ether extracts were combined, washed with 100 ml of water, 100 ml of brine, dried over magnesium sulfate and evaporated to yield the crude product which was chromatographed on silica gel (30:70 ethyl acetate/hexane) to yield 0.5 g of compound 86 as a white solid. Compounds 96 and 124 were prepared using essentially the same alkylation procedure and the mesylate of 2-octyn-1-ol or 2,4-pentadiyn-1-ol (example 93). Compound 101 was prepared following essentially the same procedure and using the mesylate of 2-hexyn-4-ene-1-ol prepared following essentially the procedure described in example 56 starting from propargyl alcohol and 1-bromo-1-propene. Compounds 102 and 103 were obtained from compound 101 by chromatography on an HPLC semiprep silica column eluting with 1:3 ethyl acetate/heptane. Example 93: 2,4-pentadiyn-1-ol To a suspension of sodamide (prepared from 20.5 g (0.89 gram atoms) of sodium and 500 ml liquid ammonia) was added dropwise at-40°C 1,4-dichloro-2-butyne (37 g, 0.3 mole). After stirring at -40°C for 30 minutes, a suspension of dry paraformaldehyde (9 g) was added portionwise in 100 ml anhydrous diethyl ether (Et 2 O). After stirring for 1 hour at -40°C, ammonium chloride (40 g, 0.75 moles) was added portionwise as a solid followed by 200 ml of Et 2 O. The ammonia was allowed to evaporate overnight and the solution was filtered through Celite. The solids were washed with Et 2 O (100 ml) and the ether layer was washed with saturated brine. The ether layer was dried over anhydrous MgSO 4 and stripped to yield 16 g of 2,4-pentadiyn-1-ol as a red oil (67% yield). Example 109: 6-(4-chlorophenyl)-2-(2'-pentynyl)pyridazinone a. 6-(4-chlorophenyl)pyridazinone To a solution of 6-(4-chlorophenyl)-4,5-dihydropyridazinone (11.75 g) and glacial acetic acid (100 ml) was added dropwise 3 ml of bromine and the mixture was heated at 60-70°C for 3 h. The resulting mixture was cooled and slowly poured into 400 ml of cold water. The resulting white solid was filtered and dried to yield 10.83 g (89%) of 6-(4-chlorophenyl)pyridazinone. b. 6-(4-chlorophenyl)-2-(2'-pentynyl)pyridazinone The pyridazinone obtained in part a above was alkylated as described in Example 6 to obtain 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone. Compounds 108, 110-118, 120, 121, 127 and 129-131 were prepared following essentially the same procedure starting with the appropriate dihydropyridazinone and alkylating agent. Example 122: 6-(4-cmorophenyl)-4,5-difluoro-2-(2'-pentynyl)-pyridazinone a. 1,4-dichloro-1,2,2-trifluorocyclobut-3-ene To a solution of 1,1,2 trichloro-2,3,3-trifluorocyclobutane (55.5 g) in 100 ml of anhydrous ether, triethylamine (40 ml) was added dropwise over 30 min at room temperature, and the mixture was stirred overnight at ambient temperature. The mixture was then stirred with 120 ml H 2 O and 7.5 ml of concentrated HCl. The ether layer was washed with H 2 O (100 ml), brine (100 ml), dried over anhydrous MgSO 4 , and evaporated in vacuo. The residue was distilled fractionally at atmospheric pressure from 64-68°C to yield 36 g (79%) of a colorless liquid as pure product. b. 2 -chloro-2,3,3-trifluorosuccinic acid To potassium hydroxide (11.3 g) in 250 ml H 2 O, potassium permanganate (56 g) was added in one portion and the mixture was stirred until everything was in solution. Then 1,4-dichloro-1,2,2-trifluorocylobutene-3-ene (31.1 g) was added dropwise at 15-20°C over 30 minutes. The mixture was stirred for 12 hours at room temperature, filtered through Celite and washed with water. The aqueous solution was acidified with 23 ml concentrated H 2 SO 4 (4x100 ml). The acid solution was extracted with ether and dried over anhydrous MgSO 4 . The ether layer was stripped to yield the product as 26 g (71%) of a colorless liquid. c. 2,2,3-trifluorosuccinic acid To a stirring solution of the chlorotrifluorosuccinic acid (part b) (24.5 g) in 200 ml dioxane was added portionwise zinc metal (85 g) and the mixture was stirred at ambient temperature for 10 hours to yield a viscous liquid which was decanted from the unreacted zinc. Most of the dioxane was evaporated in vacuo. The residue was dissolved in 100 ml H 2 O and a solution of 7.7 ml of concentrated H 2 SO 4 in 25 ml of water was added. The solution was extracted with ether (3x100 ml) and dried over anhydrous MgSO 4 . The organic layer was stripped to yield 8.3 g (32%) of the product as a crystalline solid. d. 2,2,3 -trifluorosuccinic anhydride A slurry of the succinic acid (part c) (8.0 g) and phosphorus pentoxide (14.7 g) was heated and the anhydride was distilled through a 6" Vigreux column at 15 mm Hg. The colorless liquid was collected at 60-68°C. The product was isolated in 53% yield (3.0 g). e. 6-(4-chlorophenyl)-4,5-difluoro-2-(2'-pentynyl)-pyridazinone The anhydride was reacted with chlorobenzene as described in Example 26a to produce a mixture of fluorinated ketoacids. Cydizatio with hydrazine yielded a single difluorodihydropyridazinone. Alkylation with 1-bromo-2-pentyne yielded 6-(4-chlorophenyl)-4,5-difluoro-2-(2'-pentynyl)-pyridazinone. Example 124: 6-(4-chlorophenyl)-2-(3'-tri-n-butyltin-2'-propynyl)-4,5-dihydropyridazinone A solution of 6.0 g of compound 118 in 50 ml of dry tetrahydrofuran was cooled to -78°C and 17.4 ml of 1.6 M n-butyllithium in hexane was added dropwise. The solution was stirred at -78°C for 30 minutes and then a solution of 8.0 g of tributyltin chloride in 30 ml of dry tetrahydrofuran was added dropwise. The reaction mixture was allowed to warm to room temperature and stirred overnight, then quenched with 100 ml of brine and extracted with ether (3x100 ml). The ether extracts were combined, washed will 100 ml of water, 100 ml of brine, dried and evaporated to yield a residue which was chromatographed on silica (50:50 ethyl acetate/hexane) to yield 2.1 g of compound 124 as a yellow oil. Example 143: 7-chloro-2,4,4a,5-tetrahydro-2-(2-pentyn-1-yl)-indeno[1,2-c]-pyridazin-3-one a. 2-carbomethoxy-5-chloroindanone To a mixture of sodium hydride (2.4 g, 60% in mineral oil, 0.06 mole) and 50 ml dry dimethoxyethane, 5-chloroindanone (50 g, 0.03 mole) in 50 ml dimethoxyethane was added dropwise at room temperature. The mixture was stirred at room temperature until hydrogen evolution ceased. Then dimethylcarbonate (27 g, 0.3 mole) was added dropwise at room temperature and the reaction was heated to 60°C for one hour. The reaction was cooled to room temperature, quenched with 100 ml H 2 O, acidified to pH 5 with concentrated HCl and extracted with ethyl ether (3x100 ml). The ether extract was washed with brine (100 ml), dried over anhydrous MgSO 4 and stripped to yield 3.0 g (45%) of the desired product as a tan solid. b. 2-carbomethoxy-2-carbomethoxymethyl-5-chloroindanone To a mixture of sodium hydride (0.44g, 60% in mineral oil, 0.0111 mole) and 50 ml dry dimethylformanide (DMF), the indanone ester from part a (2.5 g, 0.0111 mole) in 50 ml DMF was added dropwise with cooling. The reaction mixture was stirred at 10°C until all H 2 evolution ceased. Then methyl bromoacetate (1.9 g, 0.0122 mole) dissolved in 25 ml of DMF was added dropwise at 10°C. The reaction was stirred at 5-10°C for one hour and overnight at room temperature, then quenched with H 2 O (100 ml) and extracted with ether (3x100 ml). The organic layers were combined and washed with H 2 O (100 ml) and brine (100 ml), then dried over anhydrous MgSO 4 and stripped to yield 3.0 g of a tan solid. c. 7-chloro-2,4,4a,5-tetrahydro-indeno[1,2-c]-pyridazin-3-one A mixture of the diester (2.5 g, 0.0084 mole) from part c and 100 ml of 6N HCl was refluxed for 2 hours, until no starting material was detected by thin layer chromatography. The reaction mixture was cooled to room temperature and poured into 200 ml of ice/water. A precipitate was formed which was collected by vacuum filtration and washed with 200 ml H 2 O. The precipitate was dried overnight in vacuo at 40°C to yield 1.8 g, (95% ) white solid. d. 7-chloro-2,4,4a,5-tetrahydro-2-(2-pentyn-1-yl)-indeno(1,2-c]-pyridazin-3-one The ketoacid was reacted as described in Example 6a-b to yield Compound 143. Compound 155 was prepared following essentially the same procedure and starting with 5-chloro-3-methylindanone. Examples 145: 5-(4-chlorophenyl)-1-(2-pentyn-1-yl)-2-pyridinone a. 2-(4-chlorophenyl)-3-dimethylaminopropenal Phosphorus oxychloride (92 g) was added dropwise to stirred DMF (78 ml) between 10-15°C. To the resulting slurry was added 4-chlorophenylacetic acid (34.12 g). The resulting mixture was stirred at room temperature for one half hour and then heated to 70-80°C during 5.5 hours, during which time the mixture became effervescent. The reaction mixture was cooled and poured slowly onto cracked ice. The resulting suspension was brought to pH 10 with solid potassium carbonate. Ice was added intermittently during this addition to maintain the temperature below 15°C. Toluene (150 ml) was added and the resulting mixture heated at 100°C for one hour. The mixture was cooled and allowed to stand overnight. The two resulting layers were separated and the aqueous layer extracted with toluene (2x100 ml). The combined organic layers were washed with water (5x200 ml) and dried over anhydrous sodium sulfate. The solvent was evaporated in vacuo and the resulting yellow solid was triturated with hexane to yield 26 g of 2-(4-chlorophenyl)-3-dimethylaminopropenal as a tan solid mp. 120-125°C. b. 3-cyano-5-(4-chlorophenyl)-2-pyridinone To solution of sodium methoxide (7.52 g) in methanol (130 ml) was added cyanoacetamide (5.84 g) followed by 2-(4-chlorophenyl)-3-dimethylaminopropenal and the resulting suspension was refluxed overnight. During this time a yellow solid was formed. The mixture was cooled to room temperature and glacial acetic acid (50 ml) was added followed by water (100 ml). The resulting yellow orange solid was filtered off, washed several times with water and dried to yield 8.1 g of 3-cyano-5-(4-chlorophenyl)-2-pyridinone. c. 5-(4-chlorophenyl)-2-pyridinone A mixture of 3-cyano-5-(4-chlorophenyl)-2-pyridinone (4.6 g) and 85% H 3 PO 4 (60 ml) was heated at reflux for 16 hours. The resulting mixture was cooled to room temperature, poured into ice/water and filtered yielding 3.1 g of 5-(4-chlorophenyl)-2-pyridinone as a yellow solid. d. 5-(4-chlorophenyl)-1-(2-pentyn-1-yl)-2-pyridinone To a suspension of NaH (60% in mineral oil, 200 mg) in dry DMF (50 ml) at 0°C was added the preceding pyridinone and the mixture was stirred at 0°C for one half hour. To the resulting suspension was added 1-bromo-2-pentyne dropwise. The resulting mixture was kept at 0° C during one half hour and poured into saturated aqueous ammonium chloride (200 ml). The aqueous suspension was extracted with ether (3x100 ml) and the combined ether layers washed with brine and dried, yielding the crude product. After column chromatography (silica gel, hexane:ethyl acetate 8:2) the product was obtained as a white amorphous solid. Example 200: 4,4a,5,6-tetrahydro-8-chloro[h]-cinnolin-2-(2'-pentynyl)-3-one a. 4-(3-chlorophenyl)-butyric acid To a 300 ml round-bottomed flask equipped with magnetic stirrer and reflux condenser was charged 23.7 g of 87% potassium hydroxide and 150 ml of diethyleneglycol, With stirring, 23 g of 3-(3-chlorobenzoyl)-propionic acid was added followed by 24 g of 85% hydrazine. The mixture was heated to reflux for 2 hours when 50 ml of solvent was azeotroped off into a Dean-Stark trap. The reaction was refluxed for an additional 2 hours, cooled, and poured into 500 g of ice with 50 ml of con. hydrochloric acid. A white precipitate was formed which was extracted into 400 ml of ethyl ether, and washed with 100 ml of water and 100 ml of saturated sodium chloride solution. The ether extract was dried over anhydrous magnesium sulfate, filtered, and stripped to yield 19.5 g of product as a white solid. b. 4-(3-chlorophenyl)-butyryl chloride To a dry 100 ml flask equipped with a magnetic stirrer and reflux condenser was charged the product from part a and 20 ml of thionyl chloride. The solution was refluxed for 2 hours, cooled, and stripped to yield 18 g of product as a yellow oil. c. 6-chlorotetralone To a dry 500 ml flask equipped with side-arm addition funnel, thermometer, nitrogen inlet, and magnetic stirrer, was charged 33 g of anhydrous aluminum chloride and 200 ml of dry carbon disulfide. The product from part b (18 g) was added dropwise to the mixture and the reaction was refluxed for 2.5 hours. The reaction was then cooled and poured into 300 g of ice-water and extracted with 3x100 ml of ethyl ether. The ether extract was washed with 100 ml of water and 100 ml of saturated sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and stripped to yield 7.5 g of product as a yellow liquid. d. 6-chloro-2-(carboxymethylidene)-tetralone To a dry 250 ml flask equipped with side-arm addition funnel, thermometer, and magnetic stirrer was charged 6.7 g of sodium metaperiodate in 40 ml of water. The solution was cooled to 5° C and treated with 0.6 ml of con. sulfuric acid followed by a solution of 4.7 g of D-tartaric acid in 9 ml of water, and 20 ml of absolute ethanol. The mixture was stirred for 16 hours at room temperature, warmed to 80° C for 10 minutes, cooled, and diluted with 150 ml of water. The basic solution was washed once with 100 ml of ethyl ether, and acidified to pH 4 with 1 N hydrochloric acid. The resulting precipitate was collected by vacuum filtration and dried overnight in vacuo at 30° C to yield 7.2 g of product as a white solid. e. 6-chloro-2-(carboxylmethylene)-tetralone To a dry 100 ml flask equipped with magnetic stirrer was charged 7.2 g of the product from part d, 20 ml of water, 50 ml of glacial acetic acid, and 3.8 g of zinc dust. The reaction was warmed to 50° C for 1 hour and stirred overnight at ambient temperature. The reaction was then poured into 100 ml of ethyl acetate, filtered, and washed with 100 ml of water and 100 ml of saturated sodium chloride solution. The ethyl acetate extract was dried over anhydrous magnesium sulfate, filtered, and stripped to yield 6.0 g of product as a white solid. f. 4,4a,5,6-tetrahydro-8-chlorobenzo[h]cinnolin-3-(2H)-one The product from part e was treated with hydrazine using essentially the same procedure described for 12 d to yield 5.7 g of product as a tan solid. g. 4,4a,5,6-tetrahydro-8-chlorobenzo[h]cinnolin-2-(2'-pentynyl)-one The product was prepared from the product in part f using essentially the same procedure described for example 12 e. Example 202: 5,6-dihydro-8-chlorobenzo[h]cinnolin-3-(2'-pentynyl)-one The product from 200, part f, was oxidized and alkylated using essentially the same procedures described for example 109 a,b. Example 208: 6-(4-chlorophenyl)-2-(1-methyl-2-pentynyl)-4,5-dihydropyridazinone a. 3-hexyn-2-yl-methyl sulfonate The mesylate of 3-hexyn-2-ol was prepared using essentially th same procedure described for example 11 a. b. 6-(4-chlorophenyl)-2-(1-methyl-2-pentynyl)-4,5-dihydropyridazinone 6-(4-chlorophenyl)-4,5-dihydropyridazinone was alkylated with the product from part a using essentially the same procedure describes for example 6 b. Example 209: 6-(2-fluorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 2-fluorobenzoyl chloride using essentially the same procedures described for example 12 b-e Example 211: 6-(2-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 2-chlorobenzoyl chloride using essentially the same procedures described for example 12b-e. Example 212: 6-(2-methoxyphenyl)-2-(2'pentnyl)-4,5-dihydropyridazinone The product was prepared from 2-methoxybenzoyl chloride using essentially the same procedures described for example 12b-e. Example 214: 6-(3-fluorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 3-fluorobenzoyl chloride using essentially the same procedures described for example 12 b-e. Example 215: 6-(3-methylphenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 3-methylbenzoyl chloride using essentially the same procedures described for example 12 b-e. Example 216: 6-(3-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 3-chlorobenzoyl chloride using essentially the same procedures described for example 12 b-e. Example 222: 6-(3-bromo-4-fluorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 3-bromo-4-fluorobenzoic acid using essentially the same procedures described for example 12 b-e. Example 224: 6 -(3,4-difluorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone The product was prepared from 3,4 difluoro benzoic acid using essentially the same procedures described for example 12 b-e. According to the present invention there is further provided a method for controlling phytopathogenic fungus which comprises applying to the fungus or its habitat a fungicidally-effective amount of a compound or composition according to the invention, except that in the compound of formula (I) when R 2 , R 3 , R 4 , R 6 and R 7 are hydrogen and R 5 is chloro, R 1 may also be CH 2 C-=CCH 3 . Preferably, the habitat of the fungus is wood or rice. According to the present invention there is still further provided the use as a phytopathogenic fungicide of a compound or composition accoding to the invention, except that in the compound of formula (I), when R 2 , R 3 , R 4 , R 6 and R 7 are hydrogen and R 5 is chloro, R 1 may also beCH 2 C=CCH 3, The compounds of the present invention have fungitoxic activity, particularly against phytopathogenic fungi. They are active against fungi of a number of dasses including Deuteromycetes (Fungi Imperfecti), Basidiomycetes and Ascomycetes. More particularly, the method of this invention provides for activity against organisms including Pyricularia oryzae, Pyrenophora trichostoma, Fusarium species, Erysiphe graminis, Puccinia recondita, alsa leucostoma, Colletotrichum lagenarium, Nectria galligena, Cochliobolus miyabeanus, Thanatephorus cucumeris, Pseudocercosperella herpotrichioides, Helminthosporium species, Monilinia fructicola, Sclerotium rolfsii, Venturia inequalis, Botryotinia fuckeliana, Diaporthe citri, Rhizopus stolonifer, Verticillium albo-atrum, Phytophthora capsici, Alternaria solani, Ustilago maydis, Pythium ultimum, Leptosphaeria nodorum, Schlerotinia species, Sphaerotheca fuliginea, Gymnosporangium asiaticum, Alternaria alternata, Uncinula necator, and Podosphaera leucotricha. More particularly, rice diseases are controlled by the method of the invention. Examples of such rice diseases are seedborne diseases such as those incited by Cochliobolus miyabeanus and Pyricularia oryzae, soilborne diseases such as Fusarium species, Rhizoctonia species, and Rhizopus species, and seedling box and field diseases such as those incited by Pyricularia oryzae, Thanatephorus cucumeris and Cochliobolus miyabeanus. Additional diseases include powdery mildew incited by Sphaerotheca fulignea (e.g., cucurbit powdery mildew), Uncinula necator (e.g., grape powdery mildew), and Podosphaera leucotricha (e.g., apple powdery mildew). The compounds of the invention also control wood decay fungi such as Gleophyllum trabeum, Phialophora mutabilis, Poria palcenta and Trametes versicolor. Accordingly, the present invention also encompasses the use of the compounds as wood preservatives. The compounds of the invention can be applied as fungicidal sprays by methods commonly employed, such as conventional high-gallonage hydraulic sprays, low-gallonage sprays, air-blast, aerial sprays and dusts. Such use conveniently permits treatment of fungal infestations in crops such as vegatables, fruits, ornamentals, seeds, turf, cereal and vines among other plants. The dilution and rate of application will depend upon the type of equipment employed, the method and frequency of application desired and diseases to be controlled, but the effective amount is usually from 0.01 kilogram (kg) to 20 kg, of active ingredient (a.i.) per hectare. As a foliar fungicide, the pyridazinone is usually applied to growing plants at a rate of 0.1 to 5 and preferably from 0.125 to 0.5 kg per hectare. As a seed protectant, the amount of toxicant coated on the seed is usually at a dosage rate of 10 to 250 grams (g) and preferably from 20 to 60 g per 50 kilograms of seed. As a soil fungicide, the chemical can be incorporated in the soil or applied to the surface usually at a rate of 0.5 to 20 kg and preferably 1 to 5 kg per hectare. The compounds of the present invention are useful for the control of fungi and can be utilized at various loci such as the seed, the water surface, the soil or the foliage. For such purposes, these compounds can be used in the technical or pure form as prepared, as solutions or as formulations. The compounds are usually taken up in a carrier or are formulated so as to render them suitable for subsequent use as fungicides. For example, these chemical agents can be formulated as wettable powders, dry powders, emulsifiable concentrates, dusts, granular formulations, aerosols, or flowable emulsion concentrates. In such formulations, the compounds are extended with a liquid or solid carrier and when desired suitable surfactants are incorporated. It is usually desirable, particularly in the case of foliar spray formulations, to include adjuvants, such as wetting agents, spreading agents, dispersing agents, stickers, adhesive and the like in accordance with agricultural practices. Such adjuvants commonly used in the art can be found in McCutcheon's Emulsifiers and Detergents McCutcheon's Emulsifiers and Detergents/Functional Materials and McCutcheon's Functional Materials all published annually by McCutcheon Division of MC Publishing Company (New Jersey). In general, the compounds utilized in this invention can be dissolved in appropriate solvents such as acetone, methanol, ethanol, dimethylformamide or dimethyl sulfoxide and such solutions extended with water. The concentrations of the solution can vary from 1% to 90% with a preferred range being 5 to 50%. For the preparation of emulsifiable concentrates, the compounds of the invention can be dissolved in suitable organic solvents or a mixture of solvents, together with an emulsifying agent which permits dispersion of the fungicide in water. The concentration of the active ingredient in emulsifiable concentrates is usually 10% to 90% and in flowable emulsion concentrates; this can be as high as 75%. Wettable powders suitable for spraying can be prepared by admixing the compound with finely divided solid, such as clays, inorganic silicates and carbonates, and silicas and incorporating wetting agents, sticking agents, and/or dispersing agents in such mixtures. The concentration of active ingredients in such formulations is usually in the range of 20% to 98%, preferably 40% to 75%. A typical wettable powder is made by blending 50 parts of 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone, 45 parts of a synthetic precipitated hydrated silicon dioxide sold under the trademark Hi-Sil and 5 parts of sodium lignosulfonate (Marasperse N-22). In another preparation of a Kaolin type, (Barden) clay is used in place of the Hi-Sil in the above-wettable powder and in another such preparation 25% of the Hi-Sil is replaced with a synthetic sodium silicoaluminate sold under the trademark Zeolex 7. Dusts are prepared by mixing the compounds of the invention with finely divided inert solids which can be organic or inorganic in nature. Materials useful for this purpose include botanical flours, silicas, silicates, carbonates and clays. One convenient method for preparing a dust is to dilute a wettable powder with a finely divided carrier. Dust concentrates containing 20% to 80% of the active ingredient are commonly made and are subsequently diluted to 1% to 10% use concentration. The compounds of the present invention may be utilized in combination with other fungicides such as: (a) dithiocarbamate and derivatives such as: ferbam, ziram, maneb, mancozeb, zineb, propineb, metham, thiram, the complex of zineb and polyethylene thiuram disulfide, dazomet, and mixtures of these with copper salts; (b) nitrophenol derivatives such as: dinocap, binapacryl, and 2-sec-butyl-4,6-dinitrophenyl isopropyl carbonate; (c) heterocyclic structures such as: captan, folpet, glyodine, anilazine, ditalimfos, 4-butyl-1,2,4-triazole, 5-amino-1-[bis(dimethylamino)phosphinyl]-3-phenyl-1,2,4-triazole, etradiazole, dithianon, thioquinox, benomyl, thiabendazole, 4-(2-chlorophenylhydrazono)-3-methyl-5-isoxazolone, vinclozolin, iprodione, procymidone, triadimenol, triadimefon, bitertanol, prochloraz, fenarimol, bis-(p-chlorophenyl)-3-pyridinemethanol, bis-(p-chlorophenyl)-5- pyrimidinemethanol, triarimol,flutriafol, flusilazole, propiconazole, ectaconazole, myclobutanil, fenbuconazole (i.e., alpha-[2-(4-chlorophenyl)ethyl]-alpha-phenyl-1H-1,2,4-triazole-1-propanenitrile), hexaconazole, cyproconazole, terbuconazole, diniconazole, fluoroimide, pyridine-2-thiol-1-oxide, 8-hydroxyquinoline sulfate and metal salts thereof, 2,3-dihydro-5-carboxanilido-6-methyl-1,4-oxathiin-4,4-dioxide, 2,3-dihydro-5-carboxanilido-6-methyl-1,4-oxathiin, cis-N-[(1,1,2,2-tetrachloroethyl)thiol]-4-cydohexene-1,2-dicarboximide, cycloheximide, dehydroacetic acid, captafol, ethirimol, quinomethionate, D,L-methyl-N-(2,6-dimethylphenyl)-N-(2'-methoxyacetyl) alanine methyl ester, D,L-methyl-N-(2,6-dimethylphenyl)-N-chloroacetyl-D,L-2 aminobutyrolactone, D,L-N-(2,6-dimethylphenyl)-N-(phenylacetyl) alanine methyl ester, 5-methyl-5-vinyl-3-(3,5-dichlorophenyl)-2,4-dioxo-1,3-oxazolidine, 3-(3,5-dichlorophenyl)-5-methyl-5-(methoxymethyl)-1,3-oxazolidi-2,4-dione, 3-(3,5-dichlorophenyl) -1-isopropylcarbamoylhydantoin, 2-cyano-[N-(ethylaminocarbonyl) -2-methoximino]acetamide, fenpropimorph, fenpropidine, 2,6-dimethyl-N-tridecylmorpholine, dodemorph, and triforine; (d) miscellaneous halogenated fungicides such as: chlorothalonil, dichlone, chloroneb, tricamba, TCPN, dichloran, 2-chloro-1-nitropropane, polychloronitrobenzenes such as pentachloronitrobenzene (PCNB), and tetrafluorodichloroacetone; (e) fungicidal antibiotics such as: griseofulvin, kasugamycin, polyoxin, validamycin, and streptomycin; (f) copper-based fungicides such as: copper hydroxide, cuprous oxide, basic cupric chloride, basic copper carbonate, copper terephthalate, copper naphthenate and Bordeaux mixture; and (g) miscellaneous fungicides such as: dodine, phenylmercuric acetate, N-ethylmercuri-1,2,3,6-tetrahydro-3,6-endomethano-3,4,5,6,7,7-hexachlorophthalimide, phenylmercuric monoethanol ammonium lactate, p-dimethylaminobenzene sodium sulfonate, methyl isothiocyanate, 1-thiocyano-2,4-dinitrobenzene, 1-phenylthiosemicarbazide, nickel-containing compounds, calcium cyanamide, lime sulfur, thiophanate-methyl, flutolanil, edifenphos, isoprothiolane, probenazole, iprobenfos, tricyclazole, and pyroquilon. It is particularly advantageous to utilize the present invention in combination with a dithiocarbamate, e.g., mancozeb or maneb, for added control of non-phycomycetes fungi. The compounds of Examples 6, 9, 12, 13, 19, 21-23, 26, 28, 29, 31, 34, 37, 40, 43, 45, 46, 51, 53, 60, 62, 63, 70-74, 76, 82, 83, 89-92, 96-99, 101-104, 108-124, 126-131, 142, 143, 145 and 155 were tested for their fungicidal activity. The compounds were tested in vivo and/or in vitro against the following organisms: Pyricularia oryzae, Pyrenophora trichostoma, Fusarium species , Erysiphe graminis, Puccinia recondita,Valsa leucostoma, Colletotrichum lagenarium, Nectria galligena, Cochliobolus miyabeanus, Thanatephorus cucumeris, Pseudocercosperella herpotrichioides, Helminthosporium species, Monilinia fructicola, Sclerotium rolfsii, Venturia inequalis, Botryotinia fuckeliana, Diaporthe citri, Rhizopus stolonifer, Verticillium alboatrum, Phytophthora capsici, Alternaria solani, Ustilago maydis, Pythium ultimum, Leptosphaeria nodorum, Schlerotinia species, Sphaerotheca fuliginea, Gymnosporangium asiaticum, Alternaria alternata, Uncinula necator, and Podosphaera leucotricha, according to the following methods: I. In Vitro Tests - Fungitoxicity Assay Compounds were assayed for activity by the broth-dilution (BD) method or the agar-dilution (AD) method. In the agar-dilution method, potato dextrose agar was amended with a solution of the test compounds, solubilized in dimethyl sulfoxide or similar solvent at the concentration indicated in Table VI, then inoculated with a 6 mm plug of fungal mycelium. The radial growth was measured for each sample, and corrected for inoculum size. The percent growth inhibition is equal to the radial growth of the control sample (A) minus the radial growth of the treated sample (B) divided by the radial growth of the control sample (A) times 100 as seen by the following equation. Percent Growth Inhibition = A-B A x 100 Inhibition In the broth-dilution method, test compounds dissolved in dimethyl sulfoxide were added at the concentration indicated in Table VI to YD broth (2% dextrose, 0.4% yeast extract) and incubated with fungal inoculum for 48 hours at 28°C in an environmental shaker, at 200 rpm. Growth inhibition was determined by dry weight measurement according to the following formula: Percent growth Inhibition = Dry weight Control(mg) - Dry weight Treated (mg) Dry weight Control (mg) x 100 The results of the in vitro tests are reported in Table VI. II InVivo Tests Compounds were tested at 200 ppm as a twenty-four hour preapplication protectant test prior to inoculation. a) Rice Blast (RB) Pyricularia Oryzae Two week old M201 rice plants were inoculated with 250,000 spores per pot of Magnaporthe grisea (Pyricularia oryzae) by spraying the leaves and stems with an atomizer. The inoculated plants were incubated in a mist cabinet at 26.7°C (80°F) for 48 hours, then placed in a greenhouse environment [21.1-26.7°C (70-80°F)]. Six days after inoculation the plants were evaluated for percent disease control compared to check plants with the aid of standard area disease diagrams. b) Rice Sheath Blight (RSB) Thanatephorus cucumeris (Rhizoctonia solani) mycelia were grown for six days in potato dextrose broth in shake culture. Drained mycelial mats were blended with an approximately equal weight of rice flour and five parts water. This slurry was dispensed onto the soil surface of pots containing rice seedlings previously treated with experimental compounds. The plants were placed in a mist chamber at 25-28°C for 48 hours. Following two more days at 25°C and 70-90% relative humidity the plants were evaluated for percent disease control compared to check plants. The results of the in vivo tests are reported in Table VII. The compounds of the invention are also active against Candida albicans. Accordingly, the compounds of this invention can be used to control Candida albicans and dermatophytes, such as Trichophyton species, by application in a known pharmaceutically acceptable carrier by means known to one skilled in the art. The activity against Candida albicans was determined using the following test protocol. 1. Inoculum preparation Conidia and mycelium from the Candida albicans culture maintained on potato dextrose agar plates were lightly scraped off into yeast extract-dextrose broth (YDB) so that mostly conidia was used as inoculum. The conidial suspsension was strained through a double layer of cheesecloth to remove mycelial clumps. The inoculum mixture was placed in microtiter plates using a 12-tipped pipet. 175 microliters were placed in each well of the microtiter plates and the plates were placed in the refrigerator overnight. There were two replications. 2. Addition of the compounds The compounds to be tested were dissolved in 1:1 acetone:methanol and 100 ppm of the compound solution were placed in a well of the prepared microtiter plates. 3. Incubation and rating The microtiter plates were incubated for 7 days at room temperature after addition of the compounds. Percent control was visually estimated using a microtiter plate reading mirror. Readings were made at 1, 2, 3, and/or 7 days after treatment. The results are listed in Table VIII. % CONTROL OF GROWTH Cmpd ppm +1 +2 +3 +7 12 100 100 100 100 100 109 100 100 100 100 100 119 100 100 100 100 100 120 100 100 100 100 76 100 100 100 100 34 100 100 100 100 121 100 100 100 100 127 100 100 100 100 128 100 100 100 100 130 100 100 100 100 131 100 100 100 100 It has been found unexpectedly that compositions comprising certain specific compounds of the present invention in admixture with certain known fungicidal compounds have an enhanced i.e. synergistic - fungicidal activity, greater than the expected additive sum of the activities of the individual components of the composition. The expected activity, E, for a given combination of active fungicidal components can be calculated in accordance with the Colby formula: E= X + Y - (X*Y/100), wherein X = disease control action (in percent) of a first fungicide, Y = disease control action (in percent) of a second fungicide, and E = expected action of the first and second fungicide in admixture. [ See Colby, L. R., "Calculating synergistic and antagonistic responses of herbicide combinations", Weeds , 15. pp. 20-22 (1967) and Limpel et al., "Weeds control by ... certain combinations", Proc. NEWCL, 16, pp. 48-53 (1962).] The ratio of the fungicidal components of the composition having this enhanced property can vary over a wide range dependent upon the particular components and conditions of use. In general, such a composition will comprise at least a sufficient amount of each component in an effective ratio to produce compositional fungicidal activity greater than the expected additive sum of the activities of the individual components of the composition. Preferably, the observed, actual fungicidal activity is at least about one-half percent ( 0.5%) greater than, more preferably at least about five percent (5%) greater than the expected additive sum of the activities of the individual components of the composition. When properly measured, there is an observed E value greater than, preferably significantly greater than, the expected Colby formula-calculated E value, i.e.-(Actual E/Expected E) greater than 1; preferably (Actual E/Expected E) greater than 1.005; and more preferably (Actual E/Expected E) greater than 1.05. Thus the present invention also encompasses a fungicidal composition comprising (i) as first component one or more compounds having the formula in which A or A' is hydrogen or fluoro; B or B' is hydrogen, chloro or bromo; and C or C' is pentynyl,3-vinyl-2-propynyl,4-fluro-2-pentynyl or 5-fluoro-2-pentynyl, preferably 2-pentynyl or 3-vinyl-2-propynyl; and (ii) as a second component one or more of mancozeb, maneb, iprodione chlorothalonil, probenazole, pyroquilon and fenbuconazole. A preferred composition having enhanced fungicidal properties includes one or more compounds having the formula (XIV), wherein A is either a fluoro or hydrogen and C is either a 2'-pentynyl or a 3'-vinyl-2'-propynyl substituent. More preferred is 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone, 6-(3-fluoro-4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone, 6-(4-chlorophenyl)-2-(3'-vinyl-2'-propynyl)-pyridazinone, or 6-(3-fluoro-4-chlorophenyl)-2-(3'-vinyl-2'-propynyl)-pyridazinone. Another preferred compound in such compositions is a compound of formula XV wherein B' is chloro, A' is either a fluoro or hydrogen and C' is either a 2'-pentynyl or a 3'-vinyl-2'-propynyl substituent. More preferred is 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone, 6-(3-fluoro-4-chlorophenyl)-2-(2'-pentynyl)4,5-dihydropyridazinone, 6-(4-chlorophenyl)-2-(3'-vinyl-2'-propynyl)-4,5-dihydropyridazinone, or 6-(3-fluoro-4-chlorophenyl)-2-(3'-vinyl-2'-propynyl)-4,5-dihydropyridazinone. Preferred synergistic combinations include (i) 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone, (ii) 6-(3-fluoro-4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone, or (iii) 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone, in combination with mancozeb, probenazole, pyroquilon, iprodione, fenbuconazole, or chlorothalonil, e.g. in combination with mancozeb, probenazole, pyroquilon, iprodione or fenbuconazole. More preferred combinations are 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone in combination with mancozeb, probenazole, pyroquilon, iprodione, or fenbuconazole; and 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone in combination with chlorothalonil. Preferably, in such combinations having enhanced properties, the ratio of either pyradizinone or the dihydro pyradizinone compound to the other fungicide compound can range from 25:1 to 1:25, for example, from 20:1 to 1:20, preferably from 16:1 to 1:16. Illustrative preferred approximate ratios are as follows: (i) When Component I is a compound of formula (XIV) or (XV), for example, when component I is 6-(4-chlorophenyl)-2-(2'-pentynyl) pyridazinone, in combination with Component II preferred ratio of I/II (by ppm) more preferred ratio of I/II (1) mancozeb 20:1 to 1:20 4:1 to 1:4 (2) probenazole 20:1 to 1:20 16:1 to 1:16 (3) pyroquilon 25:1 to 1:25 16:1 to 1:16 (4) iprodione 10:1 to 1:10 4:1 to 1:4 (5) fenbuconazole 10:1 to 1:10 4:1 to 1:4 (ii) When component I is 6-(4-chlorophenyl)-2-(2'-pentynyl)4,5-dihydropyridazinone in combination with chlorothalonil, a preferred ratio is 20:1 to 1:20, more preferably a ratio of 4:1 to 1:4. (iii) when component I is 6-(3-fluoro-4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone, a preferred ratio of first to second component ranges from 25:1 to 1:25. The methods of use of the synergistic compositions of the present invention include those methods described above for the fungicides when used alone. Benefits can be obtained from the use of these synergistic combinations since lesser amounts of the fungicides can be utilized for particular applications as compared to the use of the individual compound alone or greater spectrum and length of activity at the same or lesser concentrations than those combinations of fungicides which do not have enhanced activities. The following experiments are illustrative of the compositions having enhanced activity and activities of the present invention described above, but are not intended to be limitations on the scope of these combinations: EXPERIMENTAL PROCEDURES The experiments below were performed using the relevant following procedures. Experimental compounds and commercial fungicides were tank mixed and mechanically sprayed at varying concentrations in a 1:1:2 mixture of acetone, methanol and water. Protective or preventive sprays were applied one day before spore inoculation. Curative or post-infection sprays were applied one day after spore inoculation. The spraying system utilized delivered a 200 ppm dose at the rate of 1458 liters per hectare. The following details were applicable for the specified diseases: Rice Blast Pyricularia Experiments. M-201 rice plants were inoculated with Pyricularia oryzae conidia. The spore concentration was 300,000 to 500,000 conidia per milliliter in water. An atomizer was used to apply twenty milliliters of inoculum to twenty plants per flat. The plants were placed in a humidity cabinet at 100% relative humidity for 48 hours and then placed in a greenhouse. Evaluations were made 7-8 days after inoculation. Wheat Septoria Experiments. Fielder wheat plants were inoculated with Septoria nodorum conidia. The spore concentration was approximately 3,000,000 conidia per milliliter in water. An atomizer was used to apply twenty milliliters of inoculum to twenty plants per flat. The plants were placed in a humidity cabinet at 100% relative humidity for 72 hours and then placed in a greenhouse. Evaluations were made 10 days after inoculation. Tomato Botrytis Experiments. Three week-old "Pixie" tomato plants were inoculated with Boytrytis cinerea conidia. The plants were held in dim light for two days prior to inoculation. The spore concentration was 500,000 to 650,000 conidia per milliliter of dextrose solution. An atomizer was used to apply the conidial suspension in a heavy coating to near runoff to both the upper and lower leaf surfaces and to the plant stem. The plants were kept in a continuous mist chamber with a day-night cycle and at 20 degrees centigrade for 5 days. "Disease control" was recorded as percent control based on a comparison of the unsprayed, inoculated controls and the treated, inoculated plants. The rates of application are indicated in the Tables. Rice Blast Protectant Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone (component "A") and mancozeb (component "B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 99 50 -- -- 0 12 -- -- 0 -- 200 -- 99 -- 50 -- 75 200 50 99 99 50 50 75 99 12 50 75 99 Rice Blast Curative Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone (component "A") and mancozeb (component "B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 80 50 -- -- 50 12 -- -- 0 -- 200 -- 0 -- 50 -- 0 -- 200 80 90 50 200 50 80 12 200 0 50 Rice Blast Protectant Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5- dihydropyridazinone (component "A" ) and chlorothalonil (component"B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 50 50 -- -- 50 12 -- -- 0 -- 200 -- 99 -- 50 -- 0 -- 12 -- 0 200 50 50 90 50 50 50 75 12 50 0 75 Rice Blast Protective Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone (component "A") and probenazole (component "B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 80 50 -- -- 0 12 -- -- 0 -- 200 -- 0 -- 50 -- 0 -- 12 -- 0 200 200 80 90 50 200 0 80 12 200 0 50 Rice Blast Protective Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone (component "A") and pyroquilon (component "B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 80 50 -- -- 0 12 -- -- 0 -- 200 -- 85 -- 50 -- 0 -- 12 -- 0 200 200 97 90 50 200 85 90 12 200 85 90 200 50 80 90 50 50 0 90 12 50 0 0 200 12 80 85 50 12 0 50 12 12 0 50 Wheat Septoria Preventative Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone (component "A") and iprodione (component "B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 50 50 -- -- 50 12 -- -- 0 -- 200 -- 50 -- 50 -- 0 -- 12 -- 0 200 50 50 90 50 50 50 80 12 50 0 80 Tomato Botrytis Protective Using 6-(4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone (component "A") and fenbuconazole (component "B") Rate ppm %Disease Control A B Calculated Observed 0 0 -- 0 200 -- -- 75 50 -- -- 0 -- 50 -- 75 -- 25 -- 75 -- 6 -- 50 200 50 93 90 50 50 75 90 12 50 75 90 "Amberlite", "Celite", "Zeolex", "Marasperse" and "Hi-Sil" are trademarks which may be registered in one or more of the designated countries.

Claims: A compound of the formula (I): wherein R 1 is halo(C 3 -C 6 )alkynyl, (C 3 -C 10 )alkynyl, (C 3 -C 6 )alkenyl (C 3 -C 6 )alkynyl or (C 3 -C 6 )alkynyl(C 3 -C 6 )alkenyl; R 2 is hydrogen or (C 1 -C 6 )alkyl and R 3 is hydrogen, halo or (C 1 -C 6 )alkoxy; or R 2 and R 3 together form a (C 1 -C 3 )alkylene; R 4 is hydrogen, halo or (C 1 -C 6 )alkyl; R 5 is hydrogen, halo or halo(C 1 -C 6 )alkoxy; R 6 is hydrogen or fluoro; and R 7 is hydrogen. and agronomically acceptable salts thereof; provided that, when R 2 , R 3 , R 4 , R 6 and R 7 are hydrogen and R 5 is chloro, R 1 is not CH 2 C≡CCH 3 . A compound as claimed in claim 1 wherein R 1 is 2-pentynyl, 2-hexynyl, 3-vinyl-2-propynyl, 4-fluoro-2-pentynyl, 5-fluoro-2-pentynyl, or 3-(1-propenyl)-2-propynyl, R 2 is hydrogen and R 3 is hydrogen or R 2 and R 3 together form a (C 1 -C 3 )alkylene link, R 4 is hydrogen, methyl, chloro or fluoro, R 5 is chloro, fluoro, bromo or trifluoromethoxy, R 6 is hydrogen or fluoro and R 7 is hydrogen. A compound as claimed in claim 2, wherein R 1 is 2-pentynyl; and either (i) R 4 is hydrogen, fluoro, chloro or methyl; R 5 is chloro, fluoro, bromo or trifluoromethoxy; and R 6 is hydrogen or fluoro; or (ii) R 2 , R 3 , R 6 and R 7 are hydrogen, R 5 is chloro and R 4 is hydrogen or fluoro. A compound as claimed in claim 2, wherein R 1 is 2-pentynyl or 3-vinyl-2-propynyl; R 2 and R 3 are linked together to form a (C 1 -C 3 )alkylene link; R 4 is hydrogen or fluoro; and R 5 is chloro, fluoro or bromo. A compound as claimed in claim 2, wherein R 1 is 2-hexynyl, 3-vinyl-2 -propynyl, or 3-(1-propenyl)-2-propynyl; R 4 is hydrogen or fluoro; R 5 is chloro; and R 6 is hydrogen. A compound of the formula (II): wherein R 1 is (C 3 -C 6 )alkynyl, (C 2 -C 6 )alkynyl(C 3 -C 6 )alkynyl, halo(C 3 -C 6 )alkynyl, (C 2 -C 6 )alkenyl(C 3 -C 6 )alkynyl or tri-((C 1 -C 6 )a1kyl)tin(C 3 -C 6 )alkynyl; preferably (C 3 -C 6 )alkynyl; R 2 is hydrogen or halogen, preferably fluoro; and R 3 is hydrogen or (C 1 -C 6 )alkyl; or R 2 and R 3 together form a (C 1 -C 3 )alkylene; and R 4 is hydrogen, halogen or (C 1 -C 6 )alkyl; and R 5 is hydrogen, halogen, (C 1 -C 6 )alkyl, or (C 1 -C 6 )alkoxy; and R 6 is hydrogen or halogen, preferably fluoro; and R 7 is hydrogen or halogen, preferably fluoro, and agronomically acceptable salts thereof. A compound as claimed in claim 6, wherein R 1 is 2-pentynyl, 3-vinyl-2-propynyl, 4-fluoro-2-pentynyl or 5-fluoro-2-pentynyl; R 2 and R 3 are each hydrogen or are linked together to form a (C 1 -C 3 )alkylene link; R 4 is hydrogen, fluoro or chloro; R 5 is fluoro, chloro or bromo; R 6 is hydrogen; and R 7 is hydrogen. A compound of claim 7, wherein R 1 is 3-vinyl-2-propynyl or 2-pentynyl; and either (i) R 4 is hydrogen or fluoro; and R 5 is chloro, fluoro or bromo or (ii) R 2 , R 3 , R 6 and R 7 are hydrogen; R 4 is hydrogen or fluoro and R 5 is chloro. A compound of claim 8, wherein R 1 is 2-pentynyl or 3-vinyl-2-propynyl; R 2 and R 3 are linked together to form a (C 1 -C 3 )alkylene link; R 4 is hydrogen or fluoro; and R 5 is chloro, fluoro or bromo. A compound of claim 7, wherein R 1 is 4-fluoro-2-pentynyl or 5-fluoro-2-pentynyl; R 4 is hydrogen or fluoro; and R 5 is chloro. A fungicidal composition comprising (i) as first component one or more compounds having the formula in which A or A' is hydrogen or fluoro; B or B' is hydrogen, chloro or bromo; and C or C' is 2-pentynyl, 3-vinyl-2-propynyl, 4-fluoro-2-pentynyl or 5-fluoro-2-pentynyl, preferably 2-pentynyl or 3-vinyl-2-propynyl ;and (ii) as a second component one or more of mancozeb, maneb, iprodione chlorothalonil, probenazole, pyroquilon and fenbuconazole. A composition as claimed in claim 11, wherein the first component is 6-(4-chlorophenyl)-2-(2'-pentynyl)pyridazinone and the second component is mancozeb, probenazole, pyroquilon, iprodione, or fenbuconazole. A composition as claimed in claim 11, wherein the second component is mancozeb and the ratio of first to the second component is from 20:1 to 1:20, preferably from 4:1 to 1:4. A composition as claimed in claim 11, wherein the second component is probenazole and the ratio of first component to second component is from 20:1 to 1:20, preferably from 16:1 to 1:16. A composition as claimed in claim 11, wherein the second component is pyroquilon and the ratio of first component to the second component is from 25:1 to 1:25, preferably from 16:1 to 1:16. A composition as claimed in claim 11, wherein the second component is iprodione and the ratio of first to second component is from 10:1 to 1:10, preferably from 4:1 to 1:4. A composition as claimed in claim 11, wherein the second component is fenbuconazole and the ratio of first component to second component is from 10:1 to 1:10, preferably from 4:1 to 1:4. A composition as claimed in claim 11, wherein the first component is 6-(4-chlorophenyl)-2-(2'-pentynyl)-4,5-dihydropyridazinone and the second component is chlorothalonil and the ratio of first to second component is from 4:1 to 1:4. A composition as claimed in claim 11, wherein the first component is 6-(3-fluoro-4-chlorophenyl)-2-(2'-pentynyl)-pyridazinone and the ratio of first to second component ranges from 25:1 to 1:25. A fungicidal composition which comprises an agronomically or pharmaceutically acceptable carrier and a fungicidally effective amount of a compound or composition according to any preceding claim. A method for controlling phytopathogenic fungus which comprises applying to the fungus or its habitat a fungicidally-effective amount of a compound or composition according to any preceding claim, except that in the compound of formula (I) when R 2 ,R 3 ,R 4 ,R 6 and R 7 are hydrogen and R 5 is chloro, R 1 may also be CH 2 C≡CCH 3 . A method as claimed in claim 21, wherein the habitat of said fungus is wood or rice. Use as a phytopathogenic fungicide of a compound or composition according to any one of claims 1 to 20, except that in the compound of formula (I), when R 2 , R 3 , R 4 , R 6 and R 7 are hydrogen and R 5 is chloro, R 1 may also be CH 2 C≡CCH 3 .

Inventors: EGAN ANNE RITCHIE, MICHELOTTI ENRIQUE LUIS, ROSS RONALD JR, WILSON WILLIE JOE, EGAN, ANNE RITCHIE, MICHELOTTI, ENRIQUE LUIS, ROSS, RONALD, JR., WILSON, WILLIE JOE
Applicants: ROHM & HAAS, ROHM AND HAAS COMPANY
Application year: 1991
Main classification: C07D237
IPC codes: C07D215, C07D409, C07D273, C07D263, C07D267, A01N43, C07D237, C07D271, C07D239, C07D213, C07D265, C07D243, C07D285, C07D223, C07D405, C07D521, C07D279, C07D401, C07D211, C07D403, C07D413, C07D281, C07D231, C07F7, A01N57