SOME REACTIONS OF 3-AMINO-2-CARBOETHOXY-4,6-DIMETHYLTHIENO[2,3-b]-PYRIDINE. SYNTHESIS OF SOME NEW THIENOPYRIDOPYRIMIDINES

Abstract

Thienopyridine oxazinone (1) has been prepared and explored as a precursor by its reaction with some reagents namely, ammonium acetate, aliphatic amines, aromatic amines, hydrazine hydrate, thiosemicarbazide, and ethyl glycinate to give pyridothienopyrimidines (11-VII). The pyrimidinone compound (11) was converted to the 4-chloro derivative (X) by its reaction with excess POCl₃ Interaction of the 4-chlorocompound (X) with some reagents namely, hydrazine hydrate, methyl amine, aniline, sodium thiophenolate, ethyl glycinate, thiosemicarbazide and thiourea, yielded pyridothieno-pyrimidine derivatives (XI-XVII) substituted at 4-position, respectively.     

Synthesis of 4-phenyloxazinones via DBU-catalyzed cleavage of 4-bromomethylcoumarins

A new route for ring transformation has been discovered during the reaction of 4-bromomethylcoumarins with hydroxyl amine in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), leading to the formation of pharmacologically important 1,2-oxazinones in a single step with very high yields.     

Synthesis of dimeric pyridinium bromide under silica supported approach

Abstract

Synthesis of dimeric substituted ester derivative of pyridinium salt with flexible linker units under conventional/silica supported approach. Solid-phase approach is much superior to the conventional method due to nontoxic, solvent free, easy work up procedure, and lesser reaction period. Synthesized dimeric ester derivative of pyridinium salts is showed excellent catalytic response for the preparation of oxizinone derivatives under conventional/approach.     

Multifunctional coupling agents: Synthesis and model reactions

New multifunctional coupling agents with one 2‐oxazoline group, one oxazinone group, and one allyl ether group were prepared. It was shown by means of model reactions that under the conditions of reactive extrusion, the 2‐oxazoline group and the oxazinone group reacted selectively with carboxylic groups and amino groups, respectively. The allyl ether group remained unaffected under the reaction conditions chosen. As a model reaction, the conversion of the coupling agents with 11‐aminoundecanoic acid resulted in the formation of an allyloxy‐functionalized poly(ester amide). The reaction could be performed stepwise, in the course of which the reaction of the amino group proceeded at 110 °C in solution, whereas the reaction of the carboxylic group was performed in the melt at 220 °C. Furthermore, the utilization of the coupling agents for the preparation of telechelic poly(propylene glycol) with one oxazoline group and one allyl ether group on each chain end was described. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 655–667, 2003