Hydroxybenzotriazole water

Hydroxybenzotriazole hydrate (HOBt) [2592-95-2] M 135.1, m 159-160 . Crystd from aqueous EtOH or water. [Dryland and Sheppard J Chem Soc Perkin Trans 1 125 1986.]... 

The following procedure describes the preparation and analysis of the (R)-a-methylbenzylamide of (R)-a-methylbenzenepropanoic add. A flame-dried, 10-mL, round-bottomed flask equipped with a Teflon-coated magnetic stirring bar and a rubber septum is charged with 25 mg (0.15 mmol) of (R)-a-methylbenzenepropanoic acid, 31 mg (0.23 mmol) of 1-hydroxybenzotriazole hydrate, 44 mg (0.23 mmol) of 1-(3-dimethylamino)propyl-3-ethylcarbodiimide hydrochloride, and 0.50 mL of anhydrous N,N-dimethylformamide. This mixture is stirred at 23°C for 10 min, then cooled to 0°C in an ice-water bath. To the cooled solution, 24 pL (0.19 mmol) of R-(+)-a-methylbenzylamine and 86 pL (0.62 mmol) of triethylamine are added. Within 1 min, a fine white precipitate appears. The mixture is stirred for 1 hr at 0°C, then warmed to 23°C. After stirring for 20 hr at 23°C, the mixture is transferred to a 30-mL separatory funnel with 10 mL of dichloromethane. The product solution is extracted, sequentially, with four 10-mL portions of 1 N aqueous hydrochloric acid solution, 10 mL of saturated... 

A mixture of 4 -[(methylsulfonyl)amino]-y-oxobenzenebutanoic acid and 1-hydroxybenzotriazole in dimethylformamide (DMF) under nitrogen, is treated with dibutylamine in DMF. The mixture is cooled in an ice bath and l-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) added in portions over 5 min. The mixture is stirred in the cold 1 h and overnight at room temperature. The solvent is removed in vacuo (bath temperature 35°C). The residue is treated with ice and ethyl acetate and the organic layer washed sequentially with 0.5 N monopotassium sulfate, cold 4% NaHC03, cold water and finally brine. The organic solution is dried (Na2S04) and concentrated in vacuo. The N,N-dibutyl-y-oxo-4-[(methylsulfonyl)amino]benzenebutan-amide (crystallized from ethyl acetate-hexane) is obtained. 

A slurry of methyl-l-(l-oxopropoxy)propoxy](4-phenylbutyl)phosphinyl]acetic acid (B-isomer), dried in vacuo at room temperature for 72 hours, (230.4 g, 0.6 moles) and hydroxybenzotriazole hydrate, dried, in vacuo at 80°C for 24 hours, (101.1 g, 0.66 mole) dichloromethane (sieved dried) (6 L) was chilled in an ice/acetone bath and treated with N,N-dicyclohexylcarbodiimide (136 g, 0.66 mole). The mixture was warmed to room temperature and stirred for 3 hours. The mixture was then chilled in ice/acetone and treated with (trans)-4-cyclohexyl-L-proline, hydrochloride (154.2 g, 0.66 mole) followed by diisopropylethylamine (170.7 g, 1.32 mole). The reaction mixture was stirred at room temperature for 18 hours. The mixture was then chilled, treated with water (1 L) and concentrated in vacuo to remove dichloromethane. The residue was diluted with ether (3600 ml) and water (3600 ml) and filtered. 

The mixture of (2S,3S,5S)-2-(2,6-dimethylphenoxyacetyl)amino-3-hydroxy-5-amino-l,6-diphenylhexane (100 g, 0.22 mol), 2S-(l-tetrahydro-pyrimid-2-onyl)-3-methyl butanoic acid methyl ester (44.8 g, 0.22 mol) and 750 ml DMF was cooled in an ice/water bath. N-Hydroxybenzotriazole (90.9 g, 0.67 mol), l-ethyl-3-[3-dimethylaminopropyl]carbodiimide (86 g, 0.45 mol) and triethylamine (62.5 ml, 0.45 mol) were added and the ice bath was removed, allowing the reaction mixture to stir with warming to room temperature for 5 hours. The mixture was diluted with 1000 ml of IPAC and quenched with 1000 ml of water. The mixture was shaken and separated, the aq. layer was extracted IPAC, the organics were washed with 10% HCI, solution of NaHC03 with 100 ml hexanes, then washed 500 ml water, and brine, dried over MgS04, filtered and concentrated to provide. (2S,3S,5S)-2-(2,6-dimethylphenoxyacetyl)amino-3-hydroxy-5-(2S-(l-tetrahydro-pyrimid-2-onyl)-3-methylbutanoyl)amino-l,6-diphenylhexane as a white foam. 

Add approximately 3.5 kg of triethylamine to a suspension of approximately 5 kg of para-toluenesulfonate of the benzyl ester of (2S,3aS,7aS)-2-carboxyoctahydroindole in approximately 60 kg of ethyl acetate, followed by approximately 6 kg of 1-hydroxybenzotriazole, approximately 7.5 kg of the N-[(S)-l-carbethoxybutyl]-(S)-alanine and approximately 7.0 kg of dicyclohexylcarbodiimide. Stir, cooling slightly for approximately 3 hours, then filter off the dicyclohexylurea formed and wash the organic phase with water. The dried organic phase is evaporated to dryness and benzyl ester of (2S,3aS,7aS)-l- 2-[l-(ethoxycarbonyl)-(S)-butylamino]-(S)-propionyl octahydroindole-2-carboxylic acid was obtained. Yield 92.3%. 

To the (2S)-2-benzyl-3-(l-methylpiperatin-4-ylsulfonyl)propionic acid (1.0 g, 3.064 mmol), the H-L-(4-thiazolyl)Ala amide of (2S,3R,4S)-2-amino-l-cyclohexyl-3,4-dihydroxy-6-methylheptane (1.11 g, 2.792 mmol), and 1-hydroxybenzotriazole (1.022 g, 7.563 mmol) in dimethylformamide (20 ml) was added N-methylmorpholine (0.35 ml, 3.2 mmol). The mixture was cooled to -23°C and treated with l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (0.760 g, 3.96 mmol). After 2 h at -23°C and 14 h at room temperature, the reaction was poured into saturated NaHC03 solution (100 ml) and extracted into ethyl acetate (2x50 ml) which was washed with water (2x50 ml) and brine (50 ml) and then was dried over Na2S04 and evaporated to afford 1.94 g. Recrystallization from ethanol (15 ml)/hexane (90 ml) afforded 1.55g (79%) of (2S)-2-benzyl-3-(l-methylpiperazin-4-ylsulfonyl)propionyl-(L)-(4-thiazolyl)Ala-amide of (2S,3R,4S)-2-amino-l-cyclohexyl-3,4-dihydroxy-6-methylheptane as a white solid, melting point 169°-170°C. 

A solution of the Step 7 product (0.16 mmol) and 1-hydroxybenzotriazole hydrate (0.16 mmol) in CH2C12 was cooled to 0°C, then stirred 30 minutes, and treated sequentially with pyrrolidine (0.16 mmol), 3-ethyl-3 -(dimethylamino)propyl-carbodiimide hydrochloride (0.16 mmol), and 60 pi triethylamine. Stirring was continued for additional 30 minutes at 0°C and 2 days at ambient temperature. The mixture was then partitioned between 1.5 ml water and 20 ml EtOAc and combined organic extracts washed with 1.5 ml brine, dried with Na2S04, and concentrated. 

Peptide synthesis. This water-soluble diitnide is useful for synthesis of peptides, particularly if it is used in combination with 1-hydroxybenzotriazole. The method was used extensively in a total synthesis of urogastrone, a polypeptide with 53 amino acid residues and three disulfide bonds, which controls human epidermal growth. ... 

Sheehan J, Cruickshank PA. Notes- a convenient synthesis of water-soluble carbodiimides. J. Org. Chem. 1961 26 2525-2528. Windridge GC, Jorgensen EC. 1-hydroxybenzotriazole as a 67. racemisation-suppressing reagent for the incorporation of im-Benzyl-histidine into peptides. J. Am. Chem. Soc. 1971 17 6318-6319. 68. 

A polymeric HOBt (132), which is soluble in dichloromethane, DMF or water and bears a poly (ethylene glycol) (PEG) chain (average molecular wt 4000), has been prepared from PEG-NH2 and l-hydroxybenzotriazole-5-carboxylic acid using DCC as coupling agent [135]. The corresponding active esters were prepared by reaction with an excess of carboxylic acid anhydrides and used for the synthesis of the model tetrapeptide Cbz-Leu-Ala-Gly-Val-OtBu [136]. 

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