Pyrrolo[3,4-C]pyrrole synthesis

A process for the preparation of a pyrrolo[3,4-c]pyrrole of formula ##STR84## wherein A and B are each independently of the other a group of formula ##STR85## wherein R.sub.1 and R.sub.2 are each independently of the other hydrogen, halogen, C.sub.1 -C.sub.18 alkyl, C.sub.1 -C.sub.18 alkoxy, C.sub.1 -C.sub.18 alkylmercapto, C.sub.1 -C.sub.18 alkylamino,--CN, --NO.sub.2, -phenyl, trifluoromethyl, C.sub.5 -C.sub.6 cycloalkyl, --C.dbd.N--(C.sub.1 -C.sub.18 alkyl), ##STR86## imidazolyl, pyrrazolyl, triazolyl, piperazinyl, pyrrolyl, oxazolyl, benzoxazolyl, benzothiazolyl, benzimidazolyl, morpholinyl, piperidinyl or pyrrolidinyl,

• G is --CH.sub.2 --, --CH(CH.sub.3)--, --C(CH.sub.3).sub.2 --, --CH.dbd.N--, --N.dbd.N--, --O--, --S--, --SO--, --SO.sub.2 -- or --NR.sub.7 --,
• R.sub.3 and R.sub.4 are each independently of the other hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.18 alkoxy or --CN, R.sub.5 and R.sub.6 are each independently of the other hydrogen, halogen or C.sub.1 -C.sub.6 alkyl and R.sub.7 is hydrogen or C.sub.1 -C.sub.6 alkyl,
• D' and E' are each independently of the other a group of formula ##STR87## and D' may also be hydrogen, and in formulae II, III and IV m, n and p are each independently of one another 0 or 1,
• X is C.sub.1 -C.sub.14 alkylene or C.sub.2 -C.sub.8 alkenylene,
• Y is a group --V--(CH.sub.2).sub.q --,
• Z is a group --V--(CH.sub.2).sub.r --,
• V is C.sub.3 -C.sub.6 cycloalkylene,
• q is an integer from 1 to 6, and
• r is an integer from 0 to 6,
• R.sub.8 and R.sub.9 are each independently of the other hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 alkoxy, halogen, CN, NO.sub.2, unsubstituted phenyl or phenoxy or phenyl or phenoxy which are substituted by C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen,
• Q is hydrogen, CN, Si(R.sub.8).sub.3,
• is a group C(R.sub.12)(R.sub.13)(R.sub.14), wherein R.sub.12, R.sub.13 and R.sub.14 are halogen,
• a group ##STR88## wherein R.sub.8 and R.sub.9 are as defined above, a group SO.sub.2 R.sub.15 or SR.sub.15, wherein R.sub.15 is C.sub.1 -C.sub.4 alkyl,
• a group CH(R.sub.16).sub.2, wherein R.sub.16 is unsubstituted phenyl or phenyl which is substituted by C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen,
• or
• a group of formula ##STR89## R.sub.10 and R.sub.11 are each independently of the other hydrogen, C.sub.1 -C.sub.18 alkyl a group ##STR90## wherein X, Y, R.sub.8, R.sub.9, m and n are as defined above, or R.sub.10 and R.sub.11, together with the linking nitrogen atom, form a pyrrolidinyl, piperidinyl or morpholinyl radical,
• which process comprises reacting a pyrrolo[3,4-c]pyrrole of formula ##STR91## wherein A and B are as defined above, in the desired molar ratio with a dicarbonate of formula
• E'-O-E' (IX)
• or with a trihaloacetate of formula
• (R.sub.17).sub.3 C-E' (X)
• or with a 1:1 mixture of a dicarbonate of formula IX and a dicarbonate of formula
• D'-O-D' (XI)
• or with a 1:1 mixture of a trihaloacetate of formula X and a trihaloacetate of formula
• (R.sub.17).sub.3 C-D' (XII),
• or with an azide of formula
• E'N.sub.3 (XIII),
• which may also be used in a 1:1 mixture with
• D'N.sub.3 (XIV)
• or with a carbonate of formula
• E'-OR.sub.18 (XV),
• which may also be used in a 1:1 mixture with
• D'-OR.sub.18 (XVI)
• or with an alkylidene-iminooxyformate of formula ##STR92## which may also be used in a 1:1 mixture with ##STR93## wherein D' and E' are each as defined above, R.sub.17 is chloro, fluoro or bromo, R.sub.18 is C.sub.1 -C.sub.4 alkyl or unsubstituted phenyl or phenyl which is substituted by halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or --CN, R.sub.19 is --CN or --COOR.sub.18, and R.sub.20 is unsubstituted phenyl or phenyl which is substituted by halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or --CN, in an aprotic organic solvent and in the presence of a base as catalyst, conveniently in the temperature range from 0.degree. to 400.degree. C., preferably from 20.degree. to 200.degree. C., for 2 to 80 hours, to form the pyrrolo[3,4-c]pyrrole of formula (VII);
• and then isolating, and optionally purifying, said pyrrolo[3,4c]pyrrole.