| 1. | Such a helerocycle is found in pyrylium salts .
吡喃盐就是这类的杂环。 |
| 2. | The diazirines are interesting, highly strained ring systems .
偶氮杂环丙烷是一类重要的、环内张力颇大的化合物。 |
| 3. | It represents an example of a heterocycle being formed as transient species .
它仍然是在反应中生成过渡状态的杂环的实例。 |
| 4. | The heterocyele in (4) is a masked fused ring held in abeyance .
（4）中的杂环可以看作是一个被掩蔽的，处于暂时停顿状态的稠环。 |
| 5. | The reduced heterocycle 46 conveniently separates out during the reaction .
在反应过程中被还原的杂环（46）可以方便地分离出来。 |
| 6. | The latter arises from abstraction of the somewhat lesser activated c-h bond in the dioxolane .
后者是由二氧杂环戊烷中活化较弱的C-H键离解而产生的。 |
| 7. | A number of recent variations have further demonstrated the utility of the 1, 3-dithiane system .
几种最近的变体进一步阐明了1，3-二硫杂环已烷体系的用途。 |
| 8. | The most important chemistry of dithianes, however, lies in their ability to act as a masked carbonyl group .
然而二硫杂环已烷的最重要的性质是它作为一个被掩蔽的羰基。 |
| 9. | Q represents the nonmetallic atoms necessary to complete a heterocyclic nucleus containing 5 atoms in the heterocyclic ring .
Q是形成5个原子杂环核所必须的非金属原子。 |
| 10. | Heterocylic aromatics such as pyridine and pyrimidines also give a somewhat similar set of bands in the 1600 cm region .
杂环芳香族结构类如吡啶、嘧啶类化合物在1600厘米1（625微米）区域也有相似的一组谱带。 |
