Heterocyclic analogs of xanthone

Vitvitskaya, A. S.; Noskova, M. P.; Kvitko, I. Ya.; fros, L. S.

doi:10.1007/bf00471581

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“…A detailed literature survey indicates that, synthesis of some thiochromeno [4,3-c] and [3,4-c]pyrazoles [21], pyrazolo-pyrazoles, isoxazolo-pyrazoles, pyrazolopyrimidines, pyrazolo-thiazines, pyrazolo-pyridines [22], pyrazolo [4,3-c]diazepines, pyrazolo[3,4-d]triazines, benzoxaphosphino [4,3-c]pyrazoles [23] and monomeric benzopyrano [4,3-c]pyrazoles [24] have been reported. In view of these observations it was considered of interest to synthesize some new dimeric chemical entities incorporating the two active pharmacophores namely coumarin and pyrazole in a single molecular frame work.…”

Section: Introductionmentioning

confidence: 99%

Rapid and efficient microwave assisted method for the regioselective synthesis of 8,8′‐methylene‐bis‐4‐oxo‐1H and 2H‐chromeno[4,3‐C]pyrazoles

Nagaraj

Reddy

2007

Journal of Heterocyclic Chem

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The ethyl ester of 5,5′‐methylene‐bis‐salicyclic acid 3 was prepared by the esterification of 5,5′‐methylene‐bis‐salicylic acid 2. The compound 3 on reacting with ethylacetoacetate yields 6,6′‐methylenebis‐(3‐acetyl‐4‐hydroxycoumarin) 4. The compound 4 was regioselectively converted into either 8,8′‐methylene‐bis‐(4‐oxo‐1H‐chromeno[4,3‐c]pyrazoles) 6 or 8,8′‐methylene‐bis(‐4‐oxo‐2H‐chromeno[4,3‐c]‐pyrazoles) 7 under microwave irradiation. High yields are achieved even on a gram scale, while reaction times are considerably shortened compared to conventional heating conditions.

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Section: Introductionmentioning

confidence: 99%