1-O-tert-butyl 2-O-(2,5-dioxopyrrolidin-1-yl) (2S)-pyrrolidine-1,2-dicarboxylate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condensation of BocProOSu (6.00 g.) and HDTrpOH (4.08 g.) by the salt coupling method gave BocPro-DTrpOH in 70% yield. Condensation of BocPro-DTrpOH (2.93 g.) and HGlyOBz p-toluenesulfonate salt (2.47 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DTrp-GlyOBz in 68% yield. Debenzylation of BocPro-DTrp-GlyOBz by hydrogenation with palladium catalyst gave BocPro-DTrp-GlyOH in 95% yield.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condensation of BocProOSu (6.00 g.) and HDTrpOH (4.08 g.) by the salt coupling method gave BocPro-DTrpOH in 70% yield. Condensation of BocPro-DTrpOH (2.93 g.) and HGlyOBz p-toluenesulfonate salt (2.47 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DTrp-GlyOBz in 68% yield. Debenzylation of BocPro-DTrp-GlyOBz by hydrogenation with palladium catalyst gave BocPro-DTrp-GlyOH in 95% yield.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condensation of BocProOSu (6.00 g.) and HDTrpOH (4.08 g.) by the salt coupling method gave BocPro-DTrpOH in 70% yield. Condensation of BocPro-DTrpOH (2.93 g.) and HGlyOBz p-toluenesulfonate salt (2.47 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DTrp-GlyOBz in 68% yield. Debenzylation of BocPro-DTrp-GlyOBz by hydrogenation with palladium catalyst gave BocPro-DTrp-GlyOH in 95% yield.

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A chilled mixture of BocProOSu (96.1 mmole.) and dimethylformamide (100 ml.) was added with cooling to 0° C. to a solution of HDTrpOH (0.1 mole) and potassium hydroxide (85%, 0.1 mole) in dimethylformamide (150 ml.) and water (25 ml.). The mixture was stirred for one hour at 0° C., allowed to warm to room temperature overnight, and stripped of volatiles. The residue was partitioned between ethyl acetate and aqueous citric acid (5%). Crystals which formed between the layers were collected by filtration and recrystallized from methanol-water. More product was obtained by stripping the ethyl acetate layer of ethyl acetate and recrystallizing the residue from methanol-water. The recrystallizates were combined, affording BocProD-TrpOH in 86% yield (33.1 g., m.r. 210°-213° C.). was added to warm to room temperature overnight The residue was partitioned between ethyl acetate and aqueous citric acid (5%) Crystals which formed between the layers were collected by filtration recrystallized from methanol-water More product was obtained recrystallizing the residue from methanol-water

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condesation of BocProOH (6.46 g.) and N-hydroxysuccinimide (3.5 g.) using dicyclohexylcarbodiimide gave BocProOSu in 75% yield. Condensation of BocProOSu (5.0 g.) and HDPheOH (2.75 g.) by the salt coupling method gave BocPro-DPheOH in 67% yield. Condensation of BocPro-DPheOH (3.98 g.) and HPheOMe hydrochloride salt (2.4 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DPhe-PheOMe in 74% yield. Hydrazinolysis of Boc-Pro-DPhe-PheOMe (3.14 g.) gave BocPro-DPhe-PheNHNH2 in 79% yield.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condesation of BocProOH (6.46 g.) and N-hydroxysuccinimide (3.5 g.) using dicyclohexylcarbodiimide gave BocProOSu in 75% yield. Condensation of BocProOSu (5.0 g.) and HDPheOH (2.75 g.) by the salt coupling method gave BocPro-DPheOH in 67% yield. Condensation of BocPro-DPheOH (3.98 g.) and HPheOMe hydrochloride salt (2.4 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DPhe-PheOMe in 74% yield. Hydrazinolysis of Boc-Pro-DPhe-PheOMe (3.14 g.) gave BocPro-DPhe-PheNHNH2 in 79% yield.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condesation of BocProOH (6.46 g.) and N-hydroxysuccinimide (3.5 g.) using dicyclohexylcarbodiimide gave BocProOSu in 75% yield. Condensation of BocProOSu (5.0 g.) and HDPheOH (2.75 g.) by the salt coupling method gave BocPro-DPheOH in 67% yield. Condensation of BocPro-DPheOH (3.98 g.) and HPheOMe hydrochloride salt (2.4 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DPhe-PheOMe in 74% yield. Hydrazinolysis of Boc-Pro-DPhe-PheOMe (3.14 g.) gave BocPro-DPhe-PheNHNH2 in 79% yield.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Condesation of BocProOH (6.46 g.) and N-hydroxysuccinimide (3.5 g.) using dicyclohexylcarbodiimide gave BocProOSu in 75% yield. Condensation of BocProOSu (5.0 g.) and HDPheOH (2.75 g.) by the salt coupling method gave BocPro-DPheOH in 67% yield. Condensation of BocPro-DPheOH (3.98 g.) and HPheOMe hydrochloride salt (2.4 g.) using dicyclohexylcarbodiimide and N-hydroxysuccinimide gave BocPro-DPhe-PheOMe in 74% yield. Hydrazinolysis of Boc-Pro-DPhe-PheOMe (3.14 g.) gave BocPro-DPhe-PheNHNH2 in 79% yield.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The desired compound was prepared from 6.0 g of Boc-Arg(NO2)-Gly-NH2, 40 ml of 4 N HCl-AcOEt, 3.4 ml of Et3N and 5.1 g of Boc-Pro-OSu in the same manner as in Example 26-(4).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The desired compound was prepared from 6.0 g of Boc-Arg(NO2)-Gly-NH2, 40 ml of 4 N HCl-AcOEt, 3.4 ml of Et3N and 5.1 g of Boc-Pro-OSu in the same manner as in Example 26-(4).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Boc-Pro-Thr(OBzl)-OH was prepared by coupling Boc-Pro-OSu (the N-hydroxysuccinamide ester of Boc-Pro-OH) to H-Thr (OBzl) - OH. H-Thr (OBzl)-OH.HCL was dissolved in 25 ml of water, NaHCO3 (6.21 g, 73.9 mmoles) and a solution of Boc-Pro-Osu (5.07 g, 16.25 mmoles) in 25 ml of dioxane were added. After stirring 3 hours, the reaction mixture was acidified with hydrochloric acid and the product extracted into ethyl acetate. It was washed with 0.2N HCl prepared in saturated aqueous NaCl, saturated NaCl and dried over anhydrous Na2SO4. Solvent was evaporated to yield 6.24 g (mp 120°-12.5°). the product extracted into ethyl acetate It was washed with 0.2N HCl prepared in saturated aqueous NaCl saturated NaCl and dried over anhydrous Na2SO4 Solvent was evaporated to yield 6.24 g (mp 120°-12.5°)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1.25 g of Boc-Pro-OSu [G. W. Anderson et al., J. Amer. Chem. Soc. 86, 1839 (1964)] and 0.68 g of H-His-OH are suspended in 4 ml of H2O and 2 ml of dioxan. While stirring vigorously, 2N NaOH is added by means of a pH stat at a pH value of 9.0. After 45 minutes the absorption of NaOH ceases. The now clear solution is stirred for a further 10 minutes, the pH value is adjusted subsequently to 5.0 with 4N HCl, and the whole is concentrated to approximately 5 ml. After the addition of 20 ml of H2O, the whole is again concentrated to approximately 5 ml and then purified by chromatography over a column of absorber resin, diaion HP-20 (φ=1.6 cm; length=20 cm). The bulk of this product is eluted with 20% isopropanol in H2O. The fractions that are pure according to thin layer chromatography are combined, concentrated almost to dryness and, after the addition of H2O, lyophilised, yielding Boc-Pro-His-OH in the form of an amorphous powder; Rf (E)=0.45; Rf (A)=0.21. After 45 minutes the absorption of NaOH ceases The now clear solution is stirred for a further 10 minutes the whole is concentrated to approximately 5 ml After the addition of 20 ml of H2O the whole is again concentrated to approximately 5 ml purified by chromatography over a column of absorber resin, diaion HP-20 (φ=1.6 cm; length=20 cm) The bulk of this product is eluted with 20% isopropanol in H2O concentrated almost to dryness after the addition of H2O