Synthesis of 4″-benzyloxyimino-4″-deoxyavermectin Bla derivatives

Six new 4＂-benzyloxyimino-4＂-deoxyavermectin B la derivatives were synthesized from avermectin Bla by the selective protection of C-5-hydroxy group, oxidation of C-4＂-hydroxy group, and deprotection followed by reaction with O-substituted hydroxylamine hydrochlorides. Their structures were confirmed by IR, 1H NMR, 13C NMR and MS. Insecticidal activities of the derivatives against Phopalosiphum pseudobrassicae, Spodoptera exigua and Pluteua xylosteua were evaluated.

Synthesis ofα-D-GlcpNAc-(1→2)-[α-D-ManpNAc-(1→3)-]α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap,the repeating unit of O10 antigen from Acinetobacter baumannii

An efficient synthesis ofα-D-GlcpNAc-（1→2）-[α-D-ManpNAc-（1→3）-]α-L-Rhap-（1→2）-α-L-Rhap-（1→3）-α-L-Rhap（1）, the repeating unit of the O10 antigen from Acinetobacter baumannii was achieved via sequential assembly of the building blocks,p- methoxylphenyl 2,4-di-O-benzoyl-α-L-rhamnopyranoside（2）;2-O-allyloxycarbonyl-3,4-di-O-bcnzoyl-α-L-rhamnopyranosyl tri- chloroacetimidate（3）;4-methoxylphenyl 3-O-allyloxycarbonyl-4-O-benzoyl-α-L-rhanmopyranoside（4）;2-azido-3-O-benzoyl-2- deoxy-4,6-O-isopropylidene-α-D-mannopyranosyl trichloroacetirnidatc（5）;2-azido-3,4,6-tri-O-benzoyl-2-deoxy-α,β-D-glucopyr- ano syl trichloroacetimidatc（6）.The total yield of 1 from 4 was 4.7%.

Highly efficient removal of allyloxycarbonyl(Alloc)function provides a practical orthogonal protective strategy for carbohydrates

Highly efficient removal of allyloxycarbonyl （Alloc） group was achieved in the presence of CH3COONH4, Pd[P（C6H5）3]4, and NaBH4 in MeOH-THF, within 5 min in almost quantitative yields （〉90%, isolated yield） without affecting acetyl, benzoyl, isopropylidene, benzylidene, allyl, benzyl, benzyl carbonate, or azido groups.

Synthesis of phosphorus-containing polyoxamacrocycles with one to two reactive thiophosphoryl chloride groups

Novel phosphorus-containing polyoxamacrocycles with one to two reactive thiophosphoryl chloride groups 5, 6, 7, 8 were synthesized from bishydroxyl compounds 1, 2, 3, 4 and thiophosphoryl chloride respectively. Their structures were confirmed by ^ 1H NMR, ^13C NMR, ^31p NMR and elemental analysis.

Synthesis and anti-TMV activity of novel N-(3-alkyl-1H-pyrazol-4-yl)-3-alkyl-4-substituted-1H-pyrazole-5-carboxamides

In order to investigate the biological activity of novel bis-pyrazole compounds, a series of N-（3-alkyl-5-（N-methylcarbamyl）- 1H-pyrazol-4-yl）-3-alkyl-4-substituted-lH-pyrazole-5-carboxamides were designed and synthesized with ethyl 3-alkyl-lH-pyr- azole-5-carboxylate 1 as starting materials. N-Methyl-3-alkyl-4-amino-lH-pyrazole-5-carboxamides 6 were obtained from 1 via 5 steps. 3-Alkyl-4-substitued-lH-pyrazole-5-carboxyl chlorides 4a, 4b, lla, llb, llc or 12 were also obtained from 1 via several steps. Target compounds 7a-Tg were obtained after the reaction of 6 with the above 1H-pyrazole-5-carboxyl chlorides. Preliminary bioassay showed some compounds possessing good inactivation effect against TMV （tobacco mosaic virus）. Compound 7a showed higher activity superior to ningnanmycin at a concentration of 5.0 × 10^-4 g/mE and equal activity at 1.0 × 10^-4 g/mE; 7b and 7c showed equal activity to virazole both at concentrations of 5.0 × 10^-4 g/mE and 1.0 × 10^-4 g/mL.

Synthesis and anti-TMV activity of novel N-(pyrimidin-5-yl)-N'-phenylureas

In order to find novel leading structures of pesticide, a series of N-（pyrimidin-5-yl）-N1-phenylureas （4a-4h） were designed and synthesized from 4-chloro-2-diethylamino-6-methyl-5-nitropyrimidine 1 via substitution, reduction and acylation procedures. Preliminary bioassay showed that all the target compounds processing good anti-TMV （tobacco mosaic virus） activity. Two compounds （4d and 4e） displayed higher activity superior to virazole at a concentration of 5.0 ×10^-4 g/mE.