Table 3.
Reaction yields and melting points of compounds 1b–11b.
| Compound | Method a | Yield (%) | mp (°C) |
|---|---|---|---|
| 1b | A | 73 | 197–198 |
| 2b | A | 62 | 106–108 (107.5–108.5) [8] |
| 3b | B | 65.5 | 96–98 (97.5–98.5) [8] |
| 4b | B | 84 | 66–68 (67–68) [8] |
| 5b | B | 59 | 94–96 (93.5–94.5) [8] (97–98) [12] (88–88.5) [6] (88–88.5) [9] (90–91) [17] (88) [7] 87–89 [20] |
| 6b | B | 61.5 | 58–60 (59.5–60) [8] |
| 7b | B | 87 | 168–170 (168.5–170) [8] |
| 8b | B | 83 | 167–169 (167) [7] |
| 9b | B | 50.5 | 101–102.5 |
| 10b | B | 99 | 233–235 b 248–249 [11] |
| 11b | B | 72 | 156.5–158 |
a
Method A: consecutive treatment of 2-methylbenzoxazole by sodium hydride and substituted ethyl benzoate; Method B: decomposition of the product of reaction of 2-methylbenzoxazole with benzoyl chloride.
b
Some polymorphic processes take place in the range 200–230 °C.