SU585164A1 - Method of preparing tret-alkylquinolyl-8-carbonates - Google Patents

Description

METHOD OF OBTAINING TRET-ALKYLKHINOLYL-8-CARBONATES

(54)

one

The invention relates to the field of organic synthesis, specifically to a method for producing tre7 alkylquinolyl carbonates of the general formula

where I-tert.-ScN pSvN5eNgSSCHN5) 4.

Tert-alkyloxycarbonyl derivatives of 8-hydroxyquinoline (oxine) are of interest as semi-products, they can be used as K-tert-alkyloxycarbonyl reagents, in particular, for the production of M-protected amino acids, as well as for the protection of hydroxyl function in organic compounds .

A known method for producing tert-alkylquinolyl-8-carbonates by reacting 8-hydroxyquinoline with an excess of tert-apkyloxycarbonyl chlorides

(chloro ethers) in the presence of triethylamine in tetrahydrofuran medium at a temperature of from -60 to + 20 ° C. 1L The process takes about 24-30 hours. The disadvantage of this method is

the complexity and duration of the process, the use of low temperature, the need to use hexrix, expensive solvents. K) in a rum to6, tertiary hlsfuguyu esters unstable compounds / difficult to access in its pure form can not withstand storage at normal temperature, which makes it difficult for Hie to use

under production conditions. The yield of the target products varies over a wide range and reaches 75%.

The purpose of the invention is the simplification of the process and the evolvement of the yield of tert-alkyl xnolnol-3 carbonates.

This is achieved by the fact that 8-hydroxyquinoline interacts with the corresponding di-tert Chalkylpyrocarbonate in the presence of triethylamine in SO-eS C 10-15 ldane.

The reaction goes according to the following scheme:

"S HOC

"Jjhlslsj ytya

 lUJiCJJ - “- ROH + CO,

 Jn

tThol, L7 ..- - - Example 1. A mixture of 1.5 g (10.3 mm) of oxine, 2.5 ml (11.5 mm) of ditert-butyl pyrocarbonate () and 1.5 ml of triethylamine is stirred at 50-55 After 4 hours, then diluted with ethyl acetate (30 ml), washed with 0.1N. On & O (3 X 15 MP), water 0.5 H.NaHCO, (15 ml), again with water, brine, then dried Ka-jSo and evaporated. The residue is crystallized from a mixture of cyclohexane-hexane and obtain 2.0 g of 79% tert of butyl-8 hydroxychino.lylcarbonate, m.p. 75-77C.

Example 2. The reaction is carried out analogously to example 1 at 15 minutes, after which it is diluted with 20 ml of benzene and evaporated in vacuo at the time until distilling is completed. By recrystallization of the residue from a mixture of cyclohexane-hexane, 2.2 g (87%) of t-bu- are obtained. Tyl-8-hydroxyquinolyl carbonate, mp. 757b. IR spectrum cM-t: 1770, 1380, 1280, 1150, 1255, 1105 (C. NaOCO-group).

Example 3. A mixture of 0.8 g (5.5 mM) of oxine, 1.8 g (4.9 mm) of phenyl tert-butyl pyrocarbonate and 0.8 ml of triethylamine is heated at 15 minutes, then diluted with 10 ml of benzene, evaporated in vacuo and the residue is dissolved with benzene (10 ml) and evaporated in a mixture of cyclohexane-heptane (20 ml). The solution after separating the precipitate is evaporated in vacuo and the residue is C-OR

the current is crystallized from ether / hexane 2:10 and after washing with hexane 10 {dried in vacuum. Get 1.3 g

(82.5%) phenyl-tert-butyl-8-hydroxyinol carbonate m.p. 91-92 С

Found,%: C 74.90; n 6, c, N4.21.

With 20.

b - Calculated,%: from 74.74; H 5.95;

l28SrS7ino

Claims (1)

1. The patent of Poland I 70814, cl. 12 p 1/10, 1974.