Acetone Cyanohydrin → 2-(2-hydroxyprop-2-yl)-4,4,6-trimethyl-5,6-dihydro-4H-1,3-oxazine

To a 250 ml 3-necked flask with a thermometer, a mechanical stirrer, and a 100 ml addition funnel attached was added 200 ml of concentrated H2SO4. The acid was cooled to 0°-5° C. with a dry-ice/acetone bath while 51 g (0.6 mole) of the acetone cyanohydrin was added at such a rate so as to maintain the temperature in the -10° to 10° C. range (Note--caution must be exercised in the initial stages of the addition since a vigorous exotherm occurs). After the addition of the nitrile, 59.0 g (0.5 moles) of 2-methyl-2,4-pentanediol was added again at a rate that kept the temperature in the -10° to 10° range (see the previous note). The mixture was stirred for an additional one hour then poured onto crushed ice (~5° C.). The acidic aqueous solution was then extracted twice with ether and the ether layers discarded. The acidic aqueous layer was then poured into a large beaker which contained ~400 g of NaHCO3 and ether. The beaker was cooled with an ice-water bath and was not allowed to rise pass 36° (basification with aqueous KOH resulted in more extensive decomposition due to the higher temperature attained). The ether layer was dried over K2CO3 and concentrated. The residue obtained was distilled at 43° C. (0.5 mm) to yield 24 g (0.13 mole, 26%) of product. The structure of this alcohol was confirmed by I.R. and N.M.R.

1. additionTo a 250 ml 3-necked flask with a thermometer, a mechanical stirrer, and a 100 ml addition funnel
2. additionwas added at such a rate so as
3. temperatureto maintain the temperature in the -10° to 10° C. range (Note
4. additionstages of the addition since a vigorous
5. additionwas added again at a rate that
6. customin the -10° to 10° range
7. additionthen poured
8. customonto crushed ice (~5° C.)
9. extractionThe acidic aqueous solution was then extracted twice with ether
10. additionThe acidic aqueous layer was then poured into a large beaker which
11. temperatureThe beaker was cooled with an ice-water bath
12. customto rise pass 36°
13. customresulted in more extensive decomposition due to the higher temperature
14. dry with materialThe ether layer was dried over K2CO3
15. concentrationconcentrated
16. customThe residue obtained
17. distillationwas distilled at 43° C. (0.5 mm)

ORD 기록

ord-cd70ddc54f5a4693877a3540d6ee48d4

출처 데이터셋

uspto-grants-1983_03

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US04378357