问题：哪位老师可以帮我翻译这篇文献，谢谢了
类型：求助 (悬赏分:3分)
提问：屎太浓
等级：▲
版块：有机化学问题(jimuwei,fpcwin1211,netpanda,yjgzfl,Ftian,)
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回复：8
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时间：2005-07-09 00:37:00 编辑加入/取消收藏订制/取消短消息举报该贴

Therefore, we have focused our attention on the various
process improvements, including cost reduction of expensive
raw materials. The nucleosidic phosphoramidite buildingblocks
alone contribute over 33% of the total raw material
cost today and their scale-up remains difficult. Particularly,
the phosphitylation step which employs 1H-tetrazole, a
hazardous reagent in combination with expensive phosphorus
reagents. Frequently, phosphitylation of protected nucleosides
is performed with 2-cyanoethyl-N,N-diisopropylchlorophosphoramidite,
an expensive reagent that is very reactive and
does not require activation.4 Additionally, this reagent does
not keep well at room temperature, and has the potential to
explode upon heating. As an alternative, the use of the less
reactive and relatively cheaper reagent, 2-cyanoethyl-
N,N,N`,N`-tetraisopropylphosphoramidite (Scheme 2, 5, bisreagent)
has been reported.5 However, since bis-reagent is
not reactive enough, it requires the use of an in-situ activator,
such as 1H-tetrazole. There are several inherent problems with the use of 1H-tetrazole, such as reported toxicity, an
explosive nature, and high cost.6 Also, 1H-tetrazole is acidic
(pKa 4.89) and is reported to cause unwanted detritylation
and possibly depurination during automated synthesis.7
Recently, trimethylsilyl chloride,8 4-5-dicyanoimidazole
(Figure 1, DCI)9 and pyridinium hydrochloride10 have been
reported as a substitute for 1H-tetrazole during phosphitylation
of nucleosides. In our scale-up studies of nucleosidic
phosphoramidites, we have tried all of the above activators
and found them to be unsatisfactory for a commercial
process. As a result, our exhaustive search for an ideal
activator has led us to pyridinium trifluoroacetate (Figure 1,
Py釺FA) as a reagent of choice for phosphitylation of
nucleosides. We believe that for phosphitylation reactions
Py稵FA is an excellent activator that is cheap, stable at room
temperature, less acidic than 1H-tetrazole and DCI, less toxic,
safe in handling, and highly soluble in a range of organic
solvents.

回复人：dingding,▲▲▲▲ (书到用时方恨少) 时间：2005-07-09 03:13:33 编辑	1楼
三氟醋酸盐吡啶是一种廉价、在室温下稳定，比1H-四唑和DCI酸性弱、低毒、操作安全并在一系列有机溶剂中有较高的溶解度的出色的催化剂。其余都是废话。

回复人：Noble,▲ (我爱化学我的QQ178044273 应用化学专业热爱化学化工核化学) 时间：2005-07-09 10:12:04 编辑	2楼
用金山的专业词库加翻译软件进行翻译比较好

回复人：屎太浓,▲ (成都分子实验室) 时间：2005-07-09 10:35:49 编辑	3楼
帮帮忙翻译一下吧```急用啊~~~！

回复人：dingding,▲▲▲▲ (书到用时方恨少) 时间：2005-07-09 15:32:20 编辑

4楼

该到丁香园求助，可难为死了，有些单词根本查不到，只能拼凑。也不知对不对，你应该明白大致意思，自己判断着看吧。译文如下：
因此，我们已经把注意力集中在各种工艺的改进上，包括昂贵的原材料的成本降低。The nucleosidic 亚磷酰胺结构单元独自贡献超过现今原料总成本的33%而且它们的放大存在困难。更为显著的是，亚磷酸隔离步骤使用了1H-四唑, 一种危险的试剂与昂贵的磷试剂化合。经常是，保护核苷的亚磷酸隔离使用 2-氰乙基-N,N-二异丙基氯亚磷酰胺,一种昂贵的试剂来完成，它完全反应不需要活化。4再加上，这种试剂不能在室温下良好保存，并在加热时有爆炸的可能性。作为一种可供选择的方法，使用已被报导的较小的反应性和相对便宜的试剂， 2-氰乙基-N,N,N`,N`-四异丙基亚磷酰胺 (图解 2, 5, BIS试剂)。然而，既然BIS试剂不能充分反应，就需要使用一种就地催化剂，象1H-四唑。使用1H-四唑存在几个固有的难题，象据报导的毒性、爆炸性和高成本。6同样， 1H-四唑是酸性的(pKa 4.89)并据报导在自动化合成期间导致不必要的脱三苯甲基作用并可能脱嘌吟。7最近，三甲基色氨酸甲硅烷氯化物，8 4-5-二氰基咪唑(图解 1, DCI)9和吡啶盐酸盐10已被报导，作为核苷亚磷酸隔离期间的1H-四唑的替代品。在我们放大研究在 nucleosidic亚磷酰胺中，我们已经试验过上述所有的催化剂并发现他们对于商业方法是不令人满意的。结果，我们对理想催化剂的彻底搜查导致三氟醋酸吡啶盐(图解 1,Py釺FA) 作为一种核苷亚磷酸隔离的上等的试剂。我们相信对于亚磷酸隔离反应，三氟醋酸吡啶盐是一种廉价、在室温下稳定，比1H-四唑和DCI酸性弱、低毒、操作安全并在一系列有机溶剂中有较高的溶解度的出色的催化剂。

另外，怎么叫这个名字，别人可都起名叫薄屎的。

回复人：szt001,▲ () 时间：2005-07-09 16:20:03 编辑	5楼
哈哈！！

回复人：屎太浓,▲ (成都分子实验室) 时间：2005-07-09 18:22:15 编辑	6楼
dingding太感谢了````有机会请你吃饭```` 你是哪儿人啊？

回复人：屎太浓,▲ (成都分子实验室) 时间：2005-07-09 22:39:49 编辑	7楼
dingding`````5分````

回复人：hong_shou,▲ (我想在有机化学的大海中畅游!) 时间：2005-07-10 00:26:00 编辑	8楼
hehe ,hao xiao!:)

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