A self-intermolecular cyclocondensation reaction of 3,4-dihydropyrimidine-2-thione（DHPM） to give a novel tricyclic structure containing DHPM core in the presence of diethyl azodicarboxylate（DEAD） and triphenylphos...A self-intermolecular cyclocondensation reaction of 3,4-dihydropyrimidine-2-thione（DHPM） to give a novel tricyclic structure containing DHPM core in the presence of diethyl azodicarboxylate（DEAD） and triphenylphosphine（TPP） at room temperature is reported.展开更多
Dicyclopentyl azodicarboxylate is introduced as a new azo-reagent which can be conveniently prepared in two steps and be used in the Mitsunobu reaction. Though there are no distinct difference of reactivity between DC...Dicyclopentyl azodicarboxylate is introduced as a new azo-reagent which can be conveniently prepared in two steps and be used in the Mitsunobu reaction. Though there are no distinct difference of reactivity between DCpAD and DEAD, the former is a more preferable azo-reagent for its stability.展开更多
Solubility of 2-amino-6-chloropurine in Mitsunobu solvents could be significantly improved after its exocyclic amino group is protected via N-tert-butoxycarbonylation.The bis-Boc protected 2-amino-6-chloropurine also ...Solubility of 2-amino-6-chloropurine in Mitsunobu solvents could be significantly improved after its exocyclic amino group is protected via N-tert-butoxycarbonylation.The bis-Boc protected 2-amino-6-chloropurine also shows excellent activity and N9 selectivity in the coupling with various alcohols by a Mitsunobu reaction.Then,a new practical and efficient method is established for the synthesis of penciclovir(PCV) from bis-Boc-2-amino-6-chloropurine 9 and the side chain of 5-(2-hydroxyethyl)-2,2-dimethyl-1,3-dioxane 5—the latter being a more easily prepared cyclic precursor of the diacetate side chain used in the conventional process.The coupling of 9 with 5 proceeded regioselectively at a N9 position of purine derivative for a good yield under Mitsunobu conditions.展开更多
This paper described a concise construction of （-）-EGCG （1f） （with an overall yield of 20% for seven steps based on the starting cinnamyl alcohol derivative 3）, featuring asymmetric dihydroxylation （ADH）, intr...This paper described a concise construction of （-）-EGCG （1f） （with an overall yield of 20% for seven steps based on the starting cinnamyl alcohol derivative 3）, featuring asymmetric dihydroxylation （ADH）, intra- and inter-molecular Mitsunobu reaction as key steps. Our strategy disclosed herein constitutes a new effective general synthetic approach toward the analogues of （-）-EGCG （1f）.展开更多
基金financial support from the National Nature Science Foundation of China(No.20902073)the Natural Science Foundation of Gansu Province(No.096RJZA116)Scientific and Technological Innovation Engineering program of Northwest Normal University(nwnu-kjcxgc-03-64)
文摘A self-intermolecular cyclocondensation reaction of 3,4-dihydropyrimidine-2-thione（DHPM） to give a novel tricyclic structure containing DHPM core in the presence of diethyl azodicarboxylate（DEAD） and triphenylphosphine（TPP） at room temperature is reported.
文摘Dicyclopentyl azodicarboxylate is introduced as a new azo-reagent which can be conveniently prepared in two steps and be used in the Mitsunobu reaction. Though there are no distinct difference of reactivity between DCpAD and DEAD, the former is a more preferable azo-reagent for its stability.
文摘Solubility of 2-amino-6-chloropurine in Mitsunobu solvents could be significantly improved after its exocyclic amino group is protected via N-tert-butoxycarbonylation.The bis-Boc protected 2-amino-6-chloropurine also shows excellent activity and N9 selectivity in the coupling with various alcohols by a Mitsunobu reaction.Then,a new practical and efficient method is established for the synthesis of penciclovir(PCV) from bis-Boc-2-amino-6-chloropurine 9 and the side chain of 5-(2-hydroxyethyl)-2,2-dimethyl-1,3-dioxane 5—the latter being a more easily prepared cyclic precursor of the diacetate side chain used in the conventional process.The coupling of 9 with 5 proceeded regioselectively at a N9 position of purine derivative for a good yield under Mitsunobu conditions.
基金Project supported by the National Natural Science Foundation of China （Nos. 20472025 and 20021001）.
文摘This paper described a concise construction of （-）-EGCG （1f） （with an overall yield of 20% for seven steps based on the starting cinnamyl alcohol derivative 3）, featuring asymmetric dihydroxylation （ADH）, intra- and inter-molecular Mitsunobu reaction as key steps. Our strategy disclosed herein constitutes a new effective general synthetic approach toward the analogues of （-）-EGCG （1f）.
