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74853-62-6

TRT-HIS(TRT)-OH synthesis

6synthesis methods
-

Yield:74853-62-6 82.5%

Reaction Conditions:

Stage #1: trityl chloride;L-histidine;zinc(II) chloride in acetonitrile at 30 - 40; for 0.166667 - 0.5 h;
Stage #2: with triethylamine in acetonitrile;Product distribution / selectivity;

Steps:

10.A; 10.B

Example 10:Direct preparation of pertrityl amino acid N,Nim - ditritylhistidine (Tr-His (Tr) -OH) .Method A.; 0.20 g of histidine (1.3 mmol) are added to a solution of 1.44 g of triphenylmethyl chloride (5.2 mmol) and 0.35 g of anhydrous zinc chloride (2.6 mmol) in 15 mL of MeCN, kept under stirring at 30-350C. The solution becomes clear after 10 min. Triethylamine is added rapidly (0.72 mL, 5.2 mmol) obtaining a clear solution that, after stirring for 15 min, is poured in 200 mL of water under vigorous stirring. The pH is adjusted to 3-4 with citric acid and stirring is continued for 15 min. The suspension thus obtained is filtered and the solid is washed rapidly with water. The dissolution of this solid in acetonitrile leads to the EPO precipitation of a crystalline solid which after 2 h can be filtered and washed with MeCN. 0.78 g of a solid are obtained with m.p. 192-930C (th. 0.83 g, 94.8%; an.: C 82.31(82.60), H 5.75 (5.83), N 6.61 (6.57)). Method B. 0.20 g of histidine (1.3 mmol) are dissolved in a solution of 1.08 g of triphenylmethyl chloride (3.9 mmol) and 0.18 g of anhydrous zinc chloride (1.3 mmol) in 15 mL of MeCN, kept under stirring and at a temperature not exceeding 4O0C. After 0.5 h a considerable quantity of solid precipitates which, by the subsequent addition of 0.54 mL of triethylamine (3.9 mmol) disappears almost entirely. After rapid filtration under vacuum, the clear filtrate is allowed to rest for 12 h, obtaining the precipitation of a crystalline solid. After filtration and washings with MeCN, MeCN/H2O 1:1 and methanol, the solid melts at 188-920C (an.: C 81.02(82.60), H 6.31 (5.83), 7.08 (6.57)). An analytic sample can be obtained by suspending the previous solid in MeCN, leaving the suspension under stirring at ambient temperature the suspension for 0.5 h, filtering and washing with the same procedures indicated above (0.70 g, th. 0.83 g, 82.5%; m.p. 191-920C; an.: C 82.29 (82.60), H 6.15 (5.83) , 6.87 (6.57) ) .

References:

WO2007/9944,2007,A1 Location in patent:Page/Page column 27-28

TRT-HIS(TRT)-OH Related Search: