由莰烯一步合成E型ω—乙酰基莰烯

该文报道了由莰烯直接ω－乙酰化一步合成Ｅ型ω－乙酰基莰烯，产率达３０％，产品香气良好，与文献报道的合成方法相比，路线缩短、操作简化、成本降低，本法为合成其它的ω－酰基莰烯开辟了一条可行的途径。     

卵巢癌中的表观遗传修饰

介绍了在卵巢癌的发展和治疗中表观遗传学的重要性，特别强调了在卵巢癌中内源性和获得性耐药性遗传途径中异常的DNA甲基化和组蛋白去乙酰化的重要性．通过表观遗传治疗反转肿瘤抑制基因沉寂和其他参与药物级联反应的基因沉寂为出现耐药性的卵巢癌患者带来了新的希望．     

DMAP催化合成O-乙酰基乳酸乙酯

利用4-(二甲氨基)吡啶(DMAP)为催化剂,合成了O-乙酰基乳酸乙酯.运用正交试验设计的方法,探讨了合成的最佳试验条件,并对产品进行了红外光谱、核磁共振谱分析检测.     

固体酸HMCM-41催化合成乙酸芳樟酯(英)

乙酸芳樟酯是制备高品质香精的原料，传统的制备主要是无机酸催化法及Williamson合成法，产率底，副产物多，产品质量差，品质低。本文采用中初分子筛MCM-41催化芳樟醇与乙酐反应得到很好的结果，各种实验参数被讨论，芳樟醇的转化率为99％左右，芳樟酯的收率在50％以上．     

染料中间体N-氰乙基-N-乙酰氧乙基苯胺的合成

以N-羟乙基-N-氰乙基苯胺为原料,用冰醋酸做酰化剂,合成得到了染料中间体N-氰乙基-N-乙酰氧乙基苯胺.同时讨论了原料的摩尔比、反应温度、反应时间等对反应收率的影响.得到的最佳条件为:N-羟乙基-N-氰乙基苯胺与冰醋酸的摩尔比为1:3,反应温度为140℃,常压反应精馏8 h,反应过程中将生成的水不断蒸出,得到产品N-氰乙基-N-乙酰氧乙基苯胺,纯度≥96%,收率达到89.8%.     

一个新颖的酰基化实验设计

本文探讨了氟哌酸的两个酰基化反应,及其作为教学实验的可行性。     

2-甲基-6-硝基苯胺的合成及表征

以邻硝基苯胺为原料,经乙酰化、甲基化、水解三步反应合成得到了目标产物2-甲基-6-硝基苯胺,并采用IR、1H NMR和13C NMR对产物结构进行了表征。探讨了乙酰化反应时催化剂AlCl3用量、反应温度、反应时间和乙酸酐的滴加速率对邻硝基乙酰苯胺产率的影响,以及甲基化反应中催化剂AlCl3用量、反应温度、反应时间和硫酸二甲酯的滴加速率对产物产率的影响。在最佳合成条件下,2-甲基-6-硝基苯胺的产率可达93.9%。     

Rapid reversion of aging phenotypes by nicotinamide through possible modulation of histone acetylation

Aging appears to be an irreversible process. Here we report that nicotinamide (NAA) can induce rapid and reversible reversion of aging phenotypes in human diploid fibroblasts in terms of cell morphology and senescence-associated β-galactosidase activity. Although NAA seems to enhance the replicative potential of the cells, it has little effect on their growth rate and life span, suggesting that NAA action is rather separated from the cellular replicative system. The effects are unique to NAA: none of the NAA-related compounds examined (an NAD precursor/niacin, NAD analogs, and poly(ADP-ribose) polymerase inhibitors) exerted similar effects. Thus, NAD-related metabolism and poly(ADP-ribosyl)ation are unlikely related to the NAA action. On the other hand, histone acetyltransferase (HAT) activity was elevated in NAA-exposed cells, while in aged cells, HAT activity and histone H4 acetylation were lowered. Taken together, the results suggest that NAA may cause rejuvenation by restoring, at least in part, altered gene expression in aged cells through its activation of HAT. Received 27 August 2001; received after revision 15 October 2001; accepted 15 October 2001