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US 5,705,657 AGranted
Isocyanate process for the preparation of 1,3A,8-trimethyl-1,2,3,3A, 8, 8A-hexahydro-pyrrole 2,3-B! indol-5 (3AS, 8AR) -hepthylcarbamate
AssigneeLabochim Laboratorio Chimico Internazionale S.p.A.
InventorsStefano Maiorana, Anna Bonura, Giorgio Chiodini
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Abstract
A process for the preparation of 1,3a,8-trimethyl-1,2,3,3a,8,8a-hexahydro-pyrrole2,3-b!indol-5(3aS,8aR)-he ptylcarbamate, of formula (I) ##STR1## by reacting eseroline with heptylisocyanate in the presence of a metal cyanate and of a quaternary ammonium salt, in polar aprotic solvents.
Claims13
A process for the preparation of 1,3a,8-trimethyl-1,2,3,3a,8,8a-hexahydro-pyrrole2,3-b!indol-5(3aS,8aR)-he ptylcarbamate of formula (I):
- ##STR5## characterized in that eseroline (II) is reacted with heptylisocyanate in the presence of a) catalytic amounts of either a quaternary phosphonium salt R.sup.1 R.sup.2 R.sup.3 R.sup.4 P.sup.+ X.sup.- quaternary ammonium salt R.sup.1 R.sup.2 R.sup.3 R.sup.4 N.sup.+ X.sup.-, wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 can be the same or different and are C.sub.1 -C.sub.12 alkyl or aralkyl and X is an anion, and b) catalytic amounts of a metal cyanate (MeOCN), wherein Me is an alkali metal or the equivalent of an alkaline-earth metal, in a polar aprotic solvent, according to the following scheme:
- ##STR6##
Dependencies are inferred from the claim text.