Heterocyclische ?-Enaminoester. 57. Studien zur N-Glycosidierung heterokondensierter Uracile
摘要:
N-Glycosylations of various heterocondensed uracils of the general type 4 are described. The thieno[2,3-d]pyrimidines (9a-e) afford with 1-0-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (7) the corresponding 1-ribosides (10a-e) in a modified Hilbert-Johnson-Birkofer synthesis; from these 10a was smoothly saponified to give the free riboside 11a. - In a more generally applicable stereospecific sodium salt glycosylation procedure employing alpha-acetobromglucose, the 1-glucosides 12-16 and with beta-(trimethylsilyl)ethoxymethyl chloride (SEM-Cl) a variation of acyclonucleosides 17-22 have been obtained. The structure of 18a has been confirmed by X-ray analysis.
Isolation of Intermediates in the Synthesis of Thieno[2,3-d]pyrimidine-2,4(1H,3H)-diones Using Microwave Irradiation
作者:A. Davoodnia、A. Zare-Bidaki、H. Eshghi
DOI:10.1080/10426500802048573
日期:2008.11.7
the synthesis of 3-arylthieno[2,3-d]pyrimidine-2,4(1H,3H)-diones has been developed by microwave-assisted condensation of ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate with aryl isocyanates. The intermediates, subsequently, underwent cyclization in t-butanol in the presence of potassium t-butoxide on heating to reflux to give the desired bicyclic products, 3-arylthieno[2,3-d]pyrimidine-2,4(1H,3H)-diones