4,4',4''-Tris(benzoyloxy)trityl as a new type of base-labile group for protection of primary hydroxyl groups
4,4',4''-Tris(benzoyloxy)trityl as a new type of base-labile group for protection of primary hydroxyl groups
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DOI：
10.1021/jo00166a014
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发表时间：
1983-09
影响因子：
3.6
通讯作者：
M. Sekine;T. Hata
中科院分区：
文献类型：
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作者：
M. Sekine;T. Hata
溶剂用量及三乙胺用量为：Py， 3ml；Py-CH2Cl2-Et3N, 2 mL-2 mL-196 mL (1.4 mmol)；Py-EtjN: 2 mL-196 mL （1.4 mmol）。b室温。分离到一种结构未知的含tbr的鸟嘌呤衍生物（16）。除7个反应外，其余反应均能高产出所需产物。接下来，考察了TBTr基团在酸性条件下的稳定性。在80%的乙酸中，TBTr组的去除速度比trityl组慢6倍，见表2。为了得到三羟基三乙基醚23并检验其在酸性介质中的稳定性，我们用氨在MeOH或MeOH-二氧六环中处理了7小时，但该反应导致定量转化为2和（12）附着在鸟嘌呤残留物上的TBTr基团的位置无法确定。CN键的裂解可能通过e-烷基化或n7 -烷基化发生。在后一种情况下，CN键在n7烷基化后被溴离子对l′碳的攻击而分裂。前者可以同等地考虑如下：已知鸟嘌呤残留物的06-改性会引起剧烈的变化
The amounts of the solvents and triethylamine used were as follows: Py, 3 mL; Py-CH2Cl2-Et3N, 2 mL-2 mL-196 mL (1.4 mmol); Py-EtjN: 2 mL-196 mL (1.4 mmol). b Room temperature. a TBTr-containing guanine derivative (16) of unknown structure was isolated. 12 All the reactions except for that of 7 gave the desired products in high yields. Next, the stability of the TBTr group under acidic conditions was examined. In 80% acetic acid, the TBTr group proved to be removed 6 times more slowly than the trityl group as shown in Table II. In orderto obtain the trihydroxytrityl ether 23 and examine its stability in acidic media, we treated 4 with ammonia in MeOH or in MeOH-dioxane for 7 h. How-ever, the reaction caused quantitative conversion to 2 and (12) The position of the TBTr group attached to the guanine residue could not be determined. The CN bond cleavage might occur either via the Oe-alkylation or via the N7-alkylation. In the latter case, the CN bond was split by an attack of bromide ion on the l'-carbon after the N7-alkylation. The former can be equally considered as follows: The 06-modification of the guanine residueis known to cause dramatic