In this paper, it was found that isopropylidene (1-hydroxy-3-oxo-butylidene) malonate 4 was a heat unstable compound and the one step convenient methods for preparation of 4-hydroxy-6-methyl-2-pyrone 1 and 3-carboxy-4...In this paper, it was found that isopropylidene (1-hydroxy-3-oxo-butylidene) malonate 4 was a heat unstable compound and the one step convenient methods for preparation of 4-hydroxy-6-methyl-2-pyrone 1 and 3-carboxy-4-hydroxy-6-methyl-2-pyrone 2 in good yields were reported. Isopropylidene malonate 3、diketen and triethylamine reacted in chloroform to give 2, and in the mixture of dichloromethane and chlorobenzene to offer 1.展开更多
The central V atom in bis[6-methyl-4-hydroxy-3-quinolinecarboxylate] mono(oxo)mono-hydroxy-vanadium(V) (1), synthesized by the hydrothermal treatment of ethyl 6-methyl-4-hydroxy-3-quinolinecarboxylate and V2O5, has a ...The central V atom in bis[6-methyl-4-hydroxy-3-quinolinecarboxylate] mono(oxo)mono-hydroxy-vanadium(V) (1), synthesized by the hydrothermal treatment of ethyl 6-methyl-4-hydroxy-3-quinolinecarboxylate and V2O5, has a distorted octahedral coordination geometry formed by six oxygen atoms from two oxygen atom of two hydroxy groups and two oxygen atoms of two carboxylate groups as well as one oxo group and hydroxy group. CCDC: 285592.展开更多
AIM:To simplify the procedure for synthesis of 2′ acetyl 12 hydroxy 2,3,10,11 dianhydro 6 O methyl erythromycin A(7). METHOD:Selective removal of the cladinose residue of clarithromycin was accomplished by the treatm...AIM:To simplify the procedure for synthesis of 2′ acetyl 12 hydroxy 2,3,10,11 dianhydro 6 O methyl erythromycin A(7). METHOD:Selective removal of the cladinose residue of clarithromycin was accomplished by the treatment with aqueous HCl at room temperature. Acetylation with acetic anhydride/triethylamine in methylene chloride provided the 2′ protected macrolide(9) with high yield. Then 2′ acetyl 12 hydroxy 2,3,10,11 dianhydro 6 O methyl erythromycin A(7) was synthesized from 9 which was treated with excess p toluenesulfonic acid and triethyl orthoformate at 50 ℃ in acetone.RESULT:The overall yield was 27%. The structure of the product was confirmed by IR,MS,NMR and elemental analysis. CONCLUSION: Our synthetic procedure of 7 was shorter and more convenient than that reported by Abbott Laboratories.展开更多
文摘In this paper, it was found that isopropylidene (1-hydroxy-3-oxo-butylidene) malonate 4 was a heat unstable compound and the one step convenient methods for preparation of 4-hydroxy-6-methyl-2-pyrone 1 and 3-carboxy-4-hydroxy-6-methyl-2-pyrone 2 in good yields were reported. Isopropylidene malonate 3、diketen and triethylamine reacted in chloroform to give 2, and in the mixture of dichloromethane and chlorobenzene to offer 1.
文摘The central V atom in bis[6-methyl-4-hydroxy-3-quinolinecarboxylate] mono(oxo)mono-hydroxy-vanadium(V) (1), synthesized by the hydrothermal treatment of ethyl 6-methyl-4-hydroxy-3-quinolinecarboxylate and V2O5, has a distorted octahedral coordination geometry formed by six oxygen atoms from two oxygen atom of two hydroxy groups and two oxygen atoms of two carboxylate groups as well as one oxo group and hydroxy group. CCDC: 285592.
文摘AIM:To simplify the procedure for synthesis of 2′ acetyl 12 hydroxy 2,3,10,11 dianhydro 6 O methyl erythromycin A(7). METHOD:Selective removal of the cladinose residue of clarithromycin was accomplished by the treatment with aqueous HCl at room temperature. Acetylation with acetic anhydride/triethylamine in methylene chloride provided the 2′ protected macrolide(9) with high yield. Then 2′ acetyl 12 hydroxy 2,3,10,11 dianhydro 6 O methyl erythromycin A(7) was synthesized from 9 which was treated with excess p toluenesulfonic acid and triethyl orthoformate at 50 ℃ in acetone.RESULT:The overall yield was 27%. The structure of the product was confirmed by IR,MS,NMR and elemental analysis. CONCLUSION: Our synthetic procedure of 7 was shorter and more convenient than that reported by Abbott Laboratories.
