Process for the synthesis of certain 2-amino-5-cyanothiophenes
AssigneeSandoz Ltd.
InventorArmand Jotterand
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Abstract
The invention relates to a process which comprises reacting a compound of formula I, ##STR1## in which A.sub.1 is a radical which does not compete with the activity of the ##STR2## OR A TAUTOMER THEREOF, WITH A COMPOUND OF FORMULA II, a.sub.2 -- ch.sub.2 -- cn ii in which A.sub.2 is a radical which does not compete with the activity of the --CH.sub.2 CN group of the compound of formula II but provides the vicinal methylene group with sufficient acidity to react with the .dbd.NH group of the compound of formula I, and with sulphur, To obtain a compound of formula III, ##STR3## in which A.sub.1 and A.sub.2 are as defined above, which compounds of formula III are useful as intermediates for the production of dyestuffs.
Claims18
A process for the synthesis of a compound of the formula ##STR22## comprising reacting a compound of the formula ##STR23## or a tautomer thereof, with a compound of the formula
- A.sub.2 --CH.sub.2 --CN
- and with sulfur, in an inert organic medium and at a reaction temperature ranging from room temperature to the boiling point of the reaction mixture,
- whereby a compound of the formula ##STR24## is obtained, wherein A.sub.1 is C.sub.1-8 alkyl, phenyl or phenyl substituted by 1 or 2 substituents each of which is independently halo, C.sub.1-3 alkyl, cyano or nitro, and ##STR25## cyano, C.sub.1-4 alkoxy, phenoxy, --CONR.sub.1 R.sub.2, --CSNR.sub.1 R.sub.2, --COOR.sub.3 or --COR.sub.4, wherein
- R.sub.1 is hydrogen;
- C.sub.1-8 alkyl;
- C.sub.1-8 alkyl substituted by hydroxy or phenyl;
- C.sub.5-7 cycloalkyl;
- phenyl or phenyl substituted by 1 to 3 substituents each of which is independently chloro or C.sub.1-3 alkyl,
- R.sub.2 is hydrogen, C.sub.1-8 alkyl or C.sub.1-8 -hydroxyalkyl,
- R.sub.3 is C.sub.1-8 alkyl;
- C.sub.5-7 cycloalkyl;
- C.sub.1-8 alkyl substituted by hydroxy, cyano, chloro, bromo, fluoro or phenyl;
- phenyl or phenyl substituted by methyl or ethyl,
- R.sub.4 is C.sub.1-8 alkyl;
- C.sub.1-8 alkyl substituted by hydroxy, cyano, chloro, bromo or fluoro;
- phenyl or phenyl substituted by methyl or ethyl,
- R.sub.11 is hydrogen, C.sub.1-3 alkylsulfonyl, nitro or cyano,
- R.sub.12 is hydrogen, C.sub.1-3 alkylsulfonyl, nitro, cyano, C.sub.1-3 alkyl or halo, and
- R.sub.13 is hydrogen, C.sub.1-3 alkyl or halo, with the provisos that
- (a) at least one of R.sub.11 and R.sub.12 is C.sub.1-3 alkylsulfonyl, nitro or cyano,
- (b) when one of R.sub.11 and R.sub.12 is C.sub.1-3 alkylsulfonyl, the other is other than C.sub.1-3 alkylsulfonyl, nitro or cyano, and
- (c) R.sub.13 is hydrogen when R.sub.12 is C.sub.1-3 alkyl or halo.
Dependencies are inferred from the claim text.