“…Thus, a group of Chinese researchers used squaraic acid chloride (67) in the synthesis of a series of alkyl 2-chloropyrimido[1,2-a]benzimidazole-3-carboxylates 68a-g (Scheme 21). 64 Remarkably, the study revealed that the reaction proceeds in various alcohols with the This is confirmed by a study on the synthesis of 1,4-dimethylpyrimido[1,2-a]benzimidazol-2(1H)-one (81), obtained by alkylation of pyrimidobenzimidazole 80 with dimethyl sulfate hydrate. In addition, the study provides detailed data on the properties of compound 81 revealed by X-ray structural analysis and quantum-chemical calculations (Scheme 24).…”
Section: Scheme 18mentioning
confidence: 70%
“…Thus, a group of Chinese researchers used squaraic acid chloride ( 67 ) in the synthesis of a series of alkyl 2-chloropyrimido[1,2- a ]benzimidazole-3-carboxylates 68a – g (Scheme 21 ). 64 Remarkably, the study revealed that the reaction proceeds in various alcohols with the formation of the corresponding alkyl derivatives of pyrimidobenzimidazole carboxylates 68a – g , while in aprotic solvents (MeCN, THF, and DMF) the reaction mixture underwent resinification and individual reaction products could not be isolated due to the extreme instability of the squaraic acid derivative and the resulting intermediates. Scheme 21 …”
Section: The Reaction Of Aminobenzimidazoles With Bifunctional Synthetic Equivalentsmentioning
Nitrogen-containing heterocyclic compounds are the basis of many natural and synthetic biologically active substances. 1 More than two-thirds of the known drugs used in clinical practice contain heterocyclic and, above all, nitrogen-containing fragments within their structure. Over the past decades, the chemistry of aza-heterocycles has received considerable attention due to the wide spectrum of their biological activity and numerous therapeutic applications in medicine.Of nitrogenous heterocycles, azoloazines containing fragments similar to the natural heterocycles purines and pyrimidines are currently of great practical importance. Thus, non-natural nucleosides abacavir, famciclovir, remdesivir are known, which are the products of structural modifications of all the components of the nucleotide exhibiting excellent indicators of antiviral action (Fig. 1). [2][3][4] In addition to the generally accepted nucleoside forms, the azoloazines themselves are relevant in the search for means of combating diseases on a global scale. Nitroazolo- [5,1-c][1,2,4]triazines and nitroazolo [1,5-a]pyrimidines, a new family of antiviral compounds has been found. 5 The
“…Thus, a group of Chinese researchers used squaraic acid chloride (67) in the synthesis of a series of alkyl 2-chloropyrimido[1,2-a]benzimidazole-3-carboxylates 68a-g (Scheme 21). 64 Remarkably, the study revealed that the reaction proceeds in various alcohols with the This is confirmed by a study on the synthesis of 1,4-dimethylpyrimido[1,2-a]benzimidazol-2(1H)-one (81), obtained by alkylation of pyrimidobenzimidazole 80 with dimethyl sulfate hydrate. In addition, the study provides detailed data on the properties of compound 81 revealed by X-ray structural analysis and quantum-chemical calculations (Scheme 24).…”
Section: Scheme 18mentioning
confidence: 70%
“…Thus, a group of Chinese researchers used squaraic acid chloride ( 67 ) in the synthesis of a series of alkyl 2-chloropyrimido[1,2- a ]benzimidazole-3-carboxylates 68a – g (Scheme 21 ). 64 Remarkably, the study revealed that the reaction proceeds in various alcohols with the formation of the corresponding alkyl derivatives of pyrimidobenzimidazole carboxylates 68a – g , while in aprotic solvents (MeCN, THF, and DMF) the reaction mixture underwent resinification and individual reaction products could not be isolated due to the extreme instability of the squaraic acid derivative and the resulting intermediates. Scheme 21 …”
Section: The Reaction Of Aminobenzimidazoles With Bifunctional Synthetic Equivalentsmentioning
Nitrogen-containing heterocyclic compounds are the basis of many natural and synthetic biologically active substances. 1 More than two-thirds of the known drugs used in clinical practice contain heterocyclic and, above all, nitrogen-containing fragments within their structure. Over the past decades, the chemistry of aza-heterocycles has received considerable attention due to the wide spectrum of their biological activity and numerous therapeutic applications in medicine.Of nitrogenous heterocycles, azoloazines containing fragments similar to the natural heterocycles purines and pyrimidines are currently of great practical importance. Thus, non-natural nucleosides abacavir, famciclovir, remdesivir are known, which are the products of structural modifications of all the components of the nucleotide exhibiting excellent indicators of antiviral action (Fig. 1). [2][3][4] In addition to the generally accepted nucleoside forms, the azoloazines themselves are relevant in the search for means of combating diseases on a global scale. Nitroazolo- [5,1-c][1,2,4]triazines and nitroazolo [1,5-a]pyrimidines, a new family of antiviral compounds has been found. 5 The
“…In this paper, solvation‐ and dispersion‐corrected relative Gibbs free energies (kcal/mol) are presented. All calculations were performed with the Gaussian09 software packages . (Computational Details in Supporting Information)…”
A new, efficient and simple method was designed for the synthesis of novel β‐carbonyl ester derivatives by using the PPh3‐catalyzed one‐pot method, three‐component condensation from aryl amines, aryl aldehydes and dicarbonyl ester under solvent‐free conditions. The comparative results from syntheses under these conditions provide a very simple reaction procedure that produces excellent yields and high stereoselectivity, avoids column chromatographic separation and provides an easy aqueous work‐up compared with the conventional reaction. DFT calculations were utilized to confirm and understand the mechanism of the PPh3‐catalyzed Mannich reaction. Detailed analysis of the two‐reaction pathway and their energy difference proves the stereo‐selectivity effect of the Mannich reaction, favouring anti‐isomer formation.
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