The present invention relates to novel N,N-disubstituted piperazines, 
processes for their preparation, their use as fungicides, fungicides which 
contain the novel active ingredients, and methods for controlling harmful 
fungi with these active ingredients. 
N,N-Alkyl- or aryl-disubstituted piperazine derivatives have been disclosed 
as pharmacologically active agents and as feed additives (GB 850 662, U.S. 
Pat. No. 2 943 090, BE-588 826 U.S. Pat. No. 2 927 924, DE-28 09 209, BE 
853 899, BE 840 326, DE-22 63 211, DE-20 50 684, BE 756 127, U.S. Pat. No. 
4 523 014). 
DE 30 28 483 discloses N,N'-dialkylpiperazines of the formula V 
##STR2## 
where R.sup.1 is C.sub.1 -C.sub.12 -alkyl, cycloalkyl or hydroxyalkyl and 
R.sup.2 is alkyl-substituted or cycloalkyl-substituted C.sub.6 -C.sub.20 
-aryl, as compounds which prevent bleaching of diazotypes. 
DE-2 727 482 discloses the dialkylpiperazine derivative VI as a compound 
having a fungicidal action. 
##STR3## 
It is an object of the present invention to provide novel compounds of this 
type having improved properties as fungicides. 
We have found that this object is achieved and that N,N'-disubstituted 
piperazines of the formula I 
##STR4## 
where the group is unsaturated (.dbd.) or saturated (--) and A is --, 
--CH.dbd., --CH.sub.2 -- or --CH.sub.2 --CH.sub.2 --, R.sup.1 is branched 
or straight-chain C.sub.2 -C.sub.20 -alkyl, C.sub.3 -C.sub.20 -alkenyl, 
C.sub.3 -C.sub.20 -alkynyl, C.sub.4 -C.sub.12 -cycloalkyl, C.sub.4 
-C.sub.12 -cycloalkenyl, C.sub.4 -C.sub.20 -alkylcycloalkyl, C.sub.4 
-C.sub.20 -cycloalkenylalkyl, C.sub.4 -C.sub.20 -alkylcycloalkenyl, 
C.sub.9 -C.sub.11 -bicycloalkyl, C.sub.10 -C.sub.15 -bicycloalkylalkyl or 
C.sub.10 -C.sub.15 -alkylbicycloalkyl, and these radicals may be 
unsubstituted or monosubstituted to trisubstituted by hydroxyl, 1-3 
halogen atoms, such as chlorine, bromine or fluorine, C.sub.1 -C.sub.5 
-alkoxy or C.sub.3 -C.sub.9 -trialkylsilyl, R.sup.1 may furthermore be 
5-membered to 7-membered heterocycloalkyl having 1 or 2 heteroatoms from 
the group consisting of oxygen and/or sulfur, 5-membered to 7-membered 
heterocycloalkylmethyl having 1 or 2 heteroatoms from the group consisting 
of oxygen and/or sulfur, or 5-membered to 7-membered 
heterocycloalkylmethyl which is monosubstituted to trisubstituted by 
C.sub.1 -C.sub.8 -alkyl and has 1 or 2 heteroatoms from the group 
consisting of oxygen and/or sulfur, and R.sup.2 is branched C.sub.3 
-C.sub.10 -alkyl, branched C.sub.3 -C.sub.8 -alkoxy, C.sub.3 -C.sub.7 
-cycloalkyl, trimethylsilyl or C.sub.3 -C.sub.8 -alkylthio, and their 
salts which are physiologically tolerated by plants are excellent 
fungicides and well tolerated by plants. 
Salts of the piperazines are salts with any inorganic or organic acids, for 
example with hydrochloric acid, hydrobromic acid, sulfuric acid, 
phosphoric acid, dodecylbenzenesulfonic acid, formic acid, acetic acid, 
propionic acid, palmitic acid, perfluoroheptanoic acid, oxalic acid, 
malonic acid, benzoic acid, malic acid or dodecylsulfonic acid. 
The novel [sic] N,N'-disubstituted piperazines of the formula I and their 
salts which are physiologically tolerated by plants contain chiral 
centers. They are generally obtained as racemates or may be obtained as 
diastereomeric mixtures. 
In the case of some of the novel compounds, pure diastereomeric compounds 
can be isolated, for example, by distillation or column chromatography or 
on the basis of solubility differences. Pure enantiomeric compounds can be 
obtained, for example, by resolution of racemates with a chiral auxiliary 
reagent by a known method, for example via diastereomeric salts. Both the 
diastereomers of the novel N,N'-disubstituted piperazines of the formula I 
or their salts which are physiologically tolerated by plants and their 
stereoisomeric mixtures obtained in the synthesis are suitable for use as 
fungicides. The present invention relates to all these compounds. 
Preferred compounds I are those in which A has the abovementioned meanings, 
so that the group 
##STR5## 
has, for example, the following meanings: 
##STR6## 
and R.sup.1 is C.sub.2 -C.sub.20 -alkyl, in particular C.sub.3 -C.sub.19 
-alkyl, for example propyl, isopropyl, butyl, isobutyl, but-2-yl, 
tert-butyl, pentyl, pent-2-yl, pent-3-yl, 1,2-dimethylpropyl, 
2,2-dimethylpropyl, hexyl, hex-2-yl, hex-3-yl, 2,3,3-trimethylbut-2-yl, 
4-methylpent-2-yl, 4-methylpentyl, 3,3-dimethylbutyl, heptyl, hept-2-yl, 
hept-3-yl, hept-4-yl, diisopropylmethyl, 1,4-dimethylpentyl, 
4,4-dimethylpentyl, octyl, 2-methylhept-3-yl, 5-methylhept-3-yl, oct-2-yl, 
oct-3-yl, oct-4-yl, 5,5-dimethylhexyl, 2,4,4-trimethylpentyl, 
6-methylhept-2-yl, nonyl, non-2-yl, non-3-yl, non-4-yl, non-5-yl, 
2,5,5-trimethylhexyl, 2,6-dimethylhept-4-yl, 3,5,5-trimethylhexyl, decyl, 
dec-2-yl, dec-3-yl, dec-4-yl, 2,3,5,5-tetramethylhexyl, undecyl, dodecyl, 
tridecyl, 1,5,9-trimethyldecyl or tetradecyl, C.sub.2 -C.sub.20 
-hydroxyalkyl, in particular C.sub.2 -C.sub.8 -hydroxyalkyl, for example 
hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl, hydroxyhexyl, 
hydroxyheptyl, 1-hydroxybut-2-yl or 2-hydroxybut-3-yl, C.sub.2 -C.sub.20 
-haloalkyl having 1-3 halogen atoms, such as chlorine, bromine or 
fluorine, in particular C.sub.2 -C.sub.10 -haloalkyl having 1-3 halogen 
atoms, such as chlorine, bromine or fluorine, for example 3-chloropropyl, 
6-chlorohexyl, trifluoroethyl, trichloroethyl, 5-chloropent-2-yl, 
3-chlorobut-2-yl or 3,3-dichloroprop-2-yl, C.sub.1 -C.sub.5 
-alkoxy-C.sub.2 -C.sub.20 -alkyl, in particular C.sub.2 -C.sub.4 
-alkoxy-C.sub.2 -C.sub.10 -alkyl, for example methoxyethyl, ethoxy-ethyl, 
tert-butoxyethyl, 3-tert-butoxypropyl, 4-tert-butoxybutyl, methoxypropyl, 
methoxybutyl, methoxypentyl, methoxyhexyl, ethoxyhexyl or 
3-methoxyprop-2-yl, C.sub.3 -C.sub.9 -trialkylsilyl-C.sub.2 -C.sub.20 
-alkyl, in particular C.sub.3 -C.sub.6 -trialkylsilyl-C.sub.2 -C.sub.10 
-alkyl, for example trimethylsilylethyl, trimethylsilylpropyl, 
trimethylsilylbutyl, trimethylsilylpentyl or 6-trimethylsilylhexyl, 
C.sub.3 -C.sub.20 -alkenyl, in particular C.sub.3 -C.sub.14 -alkenyl, for 
example allyl, methallyl, dimethylallyl, hexenyl or 
1,5,9-trimethyldecadienyl, C.sub.3 -C.sub.20 -alkynyl, in particular 
C.sub.3 -C.sub.14 -alkynyl, for example propargyl or 
4,4-dimethylbut-2-yn-1-yl, C.sub.4 -C.sub.12 -cycloalkyl, for example 
cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or cyclododecyl, C.sub. 4 
-C.sub.12 -hydroxycycloalkyl, for example 4-hydroxycyclohexyl, C.sub.1 
-C.sub.5 -alkoxy-C.sub.4 -C.sub.12 -cycloalkyl, such as 
4-methoxycyclohexyl or 4-tert-butoxycyclohexyl, C.sub.3 -C.sub.9 
-trialkylsilyl-C.sub.4 -C.sub.12 -cycloalkyl, for example 
4-trimethylsilylcyclohexyl, C.sub.4 -C.sub.12 -cycloalkenyl, for example 
cyclopentenyl, cyclohexenyl or cycloheptenyl, C.sub.4 -C.sub.20 
-alkylcyclohexyl, for example 3,3-dimethylcyclopentyl, 
3,3,5-trimethylcyclopentyl, 4-methylcyclohexyl, 3-methylcyclohexyl, 
3,3-dimethylcyclohexyl, 3-ethylcyclohexyl, 3,3,5-trimethylcyclohexyl, 
4-isopropylcyclohexyl, 3-ethyl-5-methylcyclohexyl, 4-tert-butylcyclohexyl, 
4-(2-methylbut-2-yl)-cyclohexyl or 
4-(2,4,4-trimethylpent-2-yl)-cyclohexyl, C.sub.4 -C.sub.20 
-alkylhydroxycycloalkyl, for example 4-hydroxy-3,6-dimethylcyclohexyl, 
4-hydroxy-3,3-dimethylcyclohexyl or 4-hydroxy-3,3,5-trimethylcyclohexyl, 
C.sub.4 -C.sub.20 -cycloalkylalkyl, for example cyclohexylmethyl, 
cyclohexylethyl or cyclohexylpropyl, C.sub.4 -C.sub.20 -alkylcycloalkenyl, 
for example 4-isopropylcyclohexenyl or 4-tert-butylcyclohexenyl, C.sub.9 
-.sub.11 -bicyclo-alkyl, for example bicyclo[4.3.0]nonyl or decalyl, 
C.sub.9 -C.sub.11 -hydroxybicycloalkyl, for example 6-hydroxy-2-decalyl or 
7-hydroxy-2-decalyl, C.sub.10 -C.sub.15 -alkylbicycloalkyl, for example 
9-methyl-2-decalyl, 5,9-dimethyl-2-decalyl or 5,5,9-trimethyl-2-decalyl, 
C.sub.10 -C.sub.15 -alkylhydroxybicycloalkyl, for example 
6-hydroxy-9-methyl-2-decalyl, 6-hydroxy-5,9-dimethyl-2-decalyl or 
6-hydroxy-5,5,9-trimethyl-2-decalyl, C.sub.8 -C.sub.10 -alkoxycycloalkyl, 
for example 1,4-dioxaspiro[4,5]decan-8-yl, 5-membered to 7-membered 
heterocycloalkyl having 1 or 2 heteroatoms from the group consisting of 
oxygen and sulfur, for example tetrahydropyranyl, tetrahydrothiopyranyl or 
dioxanyl, 5-membered to 7-membered heterocycloalkylmethyl having 1 or 2 
heteroatoms from the group consisting of oxygen and sulfur, for example 
tetrahydropyranylmethyl or dioxanylmethyl, or C.sub.1 -C.sub.8 
-alkyl-substituted 5-membered to 7-membered heterocycloalkylmethyl having 
1 or 2 heteroatoms from the group consisting of oxygen and sulfur, for 
example 3,5-diethyldioxan-2-ylmethyl, 3,6-diethyldioxan-2-ylmethyl or 
3,5-dimethyldioxan-2-ylmethyl, and R.sup.2 is branched C.sub.3 -C.sub.10 
-alkyl or branched C.sub.3 -C.sub.8 -alkoxy, for example isopropyl, 
sec-butyl, isobutyl, tert-butyl, 2-methylbut-2-yl, 
2,4,4-trimethylpent-2-yl, i-propyl, sec-butoxy or tert-butoxy, C.sub.3 
-C.sub.7 -cycloalkyl, such as cyclopentyl, cyclohexyl or cycloheptyl, or 
C.sub.3 -C.sub.8 -alkylthio, for example tert-butylthio, sec-butylthio, 
isobutylthio or n-butylthio. 
The compounds of the formula I can be prepared, for example, by 
N-alkylation of an N-alkylpiperizine of the structure II 
##STR7## 
(a) Reaction of a compound II with a compound R.sup.1 -X under basic 
conditions 
Examples of radicals X are chlorine, bromine, iodine, methanesulfonyl, 
benzenesulfonyl, p-toluenesulfonyl and the radicals corresponding to the 
abovementioned anions X. 
The reaction is carried out, for example, at 40.degree.-200.degree. C., in 
the presence or absence of an inert solvent. Preferred bases are inorganic 
bases, for example potassium hydroxide, sodium hydroxide, lithium 
hydroxide, sodium hydride, potassium carbonate or sodium carbonate. 
Organic bases, such as triethylamine, dicyclohexylamine and 
diisopropylamine, are also suitable. The reaction can also be carried out 
using an excess of the piperazine derivative II. 
(b) Reaction of a carbonyl compound III 
##STR8## 
where the radicals R.sup.3 to R.sup.5 are defined so that the radical IV 
##STR9## 
in its entirety corresponds to the radical R.sup.1, with a piperazine 
derivative II with simultaneous or subsequent reduction or hydrogenation. 
(b.sub.1) In the direct method for the preparation of a compound I, a 
mixture of II and III is reacted with sodium cyanoborohydride or sodium 
borohydride in the presence of a solvent, for example methanol, ethanol, 
propanol or isopropanol, which may contain up to 25% by volume of water, 
and in the presence or absence of a metal salt, for example zinc(II) 
chloride, at 0.degree.-100.degree. C., preferably 20.degree.-80.degree. 
C., or with hydrogen in the presence of a solvent, for example methanol, 
ethanol, tetrahydrofuran or toluene, and of a hydrogenation catalyst, for 
example Raney nickel, platinum(IV) oxide, Ru.sub.2 O.sub.3 or palladium on 
carbon, in an autoclave at 100.degree.-150.degree. C. until the pressure 
remains constant. 
(b.sub.2) In the two-stage reaction, an enamine is prepared from the 
compounds II and III under dehydrating conditions, and the said enamine is 
then reduced using a noble metal catalyst, such as Raney nickel, Raney 
cobalt, PtO.sub.2 or Ru.sub.2 O.sub.3, preferably palladium on carbon, and 
hydrogen. 
The N-monosubstituted piperazines II used as starting compounds can be 
prepared by reactions which synthesize the piperazine ring (cf. for 
example PRATT, Y.T.: The Pyrazines and Piperazines, in: R. C. ELDERFIELD 
(Editor): Heterocyclic Compounds, Vol. 6, New York-London, 1957) or by 
derivatization of pyrazine derivatives. Possible syntheses are shown in 
scheme 1. 
(a) For example, a substituted amine VII can be reacted with diethanolamine 
with acid catalysis (HCl, HBr or H.sub.2 SO.sub.4) at 
200.degree.-250.degree. C. or with N,N-bischloroethylamine in an organic 
solvent, for example diethyleneglycol dimethyl ether, ethanol, acetone, 
acetone/water or dimethylformamide, in the presence of an auxiliary base, 
such as potassium carbonate or sodium carbonate, at 60.degree.-250.degree. 
C. to give II. 
Where the compound VII is an aniline, the N-cyclohexylpiperazine derivative 
II' can be obtained from the resulting N-phenylpiperazine derivative II by 
catalytic hydrogenation. 
(b) The cycloaliphatically N-substituted piperazines II' can also be 
obtained via reductive amination of N-formylpiperazine VIII with a 
correspondingly substituted cycloalkanone IX and a suitable reducing 
agent, for example sodium cyanoborohydride/zinc chloride, in methanol at 
20.degree.-60.degree. C. and subsequent alkaline hydrolysis of the 
N-formyl-N'-cycloalkylpiperazine derivative X.