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Synthesis of Derivatives of Pyrido[4,3‐ d ]pyrimidin‐4(3 H )‐one via an Iminophosphorane
Author(s) -
Liu JianChao,
He HongWu,
Ren QingYun,
Ding MingWu
Publication year - 2006
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200690133
Subject(s) - chemistry , isocyanate , carbodiimide , aryl , wittig reaction , crystal structure , catalysis , phenols , medicinal chemistry , organic chemistry , stereochemistry , polymer chemistry , alkyl , polyurethane
A series of new, 2‐substituted 3‐aryl‐8,9,10,11‐tetrahydro‐5‐methyl[1]benzothieno[3′,2′ : 5,6]pyrido[4,3‐ d ]pyrimidin‐4(3 H )‐ones, compounds 5a – q , were designed and synthesized via the aza‐ Wittig reaction as the key step. The iminophosphorane 1 reacted with phenyl isocyanate (or 4‐chlorophenyl isocyanate) to the carbodiimide 4 , which was cyclized to 5 upon addition of different amines, EtOH, or phenols in the presence of a catalytic amount of EtONa or K 2 CO 3 ( Schemes 1 and 2 ). The structures of compounds 5 were confirmed by IR, 1 H‐ and 13 C‐NMR, EI‐MS, elemental analyses, and, in the case of 5l , by single‐crystal X‐ray diffraction ( Figure ).