Claims
- 1. A method for forming a substantially pure protected peptide of the formula A.sub.1 --A.sub.2 --A.sub.3 --A.sub.4 --A.sub.5 --A.sub.6 --A.sub.7 which comprises:
- reacting a peptide fragment of the formula
- X--A.sub.2 --Y
- with a peptide fragment of the formula
- U--V--W
- in a polar solvent which solubilizes the two fragments, in the presence of a dehydrating agent and activating agent under conditions sufficient for the fragments to react,
- wherein said X--A.sub.2 --Y is Prot-A.sub.1 (protecting group)-A.sub.2 --A.sub.3 --A.sub.4 --OH and further wherein A.sub.1 is Ala or Lys, A.sub.2 is His, A.sub.3 is DTrp, DPhe, D.sup..beta. Nal or D.sup..alpha. Nal, and A.sub.4 is Ala, and
- wherein said U--V--W is 2NH--A.sub.5 --A.sub.6 --A.sub.7 (protecting group)--NH.sub.2, further wherein A.sub.5 is Trp, A.sub.6 is DPhe and A.sub.7 is Lys, and said substantially pure protected peptide is separated by precipitation.
- 2. The method of claim 1 wherein a peptide of the formula (Boc)--Lys(Boc)--His--D--Trp--Ala--Trp--D--Phe--Lys(Boc)--NH.sub.2 is formed, which comprises reacting a peptide fragment of the formula (Boc)--Lys(Boc)--His--D--Trp--Ala with a peptide fragment of the formula Trp--D--Phe--Lys(Boc)--NH.sub.2 in a suitable solvent in the presence of a dehydrating agent and activating agent under conditions sufficient for the fragments to react which involves subsequent to reaction the precipitative purification of (Boc)--Lys(Boc)--His--D--Trp--Ala--Trp--D--Phe--Lys(Boc)--NH.sub.2.
- 3. The method of claim 2 wherein said solvent is dimethylformamide solvent, said dehydrating agent is a carbodiimide and said activating agent is N-hydroxysuccinimide.
- 4. The method of claim 3 wherein the reaction proceeds at a reaction temperature of -10.degree. to 30.degree. C. and wherein, subsequent to said reaction, there is precipitative purification from ethyl acetate of (boc)--Lys(Boc)--His--D--Trp--Ala--Trp--D--Phe--Lys--(Boc)--NH.sub.2.
- 5. The method according to claim 3 which additionally involves treatment of the peptide produce, (Boc)--Lys--(Boc)--His--D--Trp--Ala--Trp--D--Phe--Lys--(Boc)--NH.sub.2, under acidic conditions to form a peptide of the formula Lys--His--D--Trp--Ala--Trp--D--Phe--Lys--NH.sub.2.
- 6. The method of claim 1, wherein a racemization inhibitor is also added to the solvent.
- 7. A method of claim 6 wherein said racemization inhibitor is 1-hydroxybenzotriazole or N-hydroxysuccinimide.
- 8. A method of forming a substantially pure protected peptide of the formula benzyloxycarbonyl-His--D--Trp--Ala--Trp--D--Phe--Lys(Boc)--NH.sub.2 which comprises reacting a peptide fragment of the formula benzyloxycarbonyl-His--D--Trp--Ala with a peptide fragment of the formula Trp--D--Phe--Lys(Boc)--NH.sub.2 in a polar solvent in the presence of a dehydrating agent and activating agent under conditions sufficient for the fragments to react which involves subsequent to reaction the precipitative purification of benzyloxycarbonyl-His--D--Trp--Ala--Trp--D--Phe--Lys(Boc)--NH.sub.2.
- 9. The method according to claim 8 wherein said solvent is dimethylformamide, said dehydrating agent is a carbodiimide and said activating agent is N-hydroxysuccinimide.
- 10. The method of claim 9 wherein the reaction proceeds at a reaction temperature of -10.degree. to 30.degree. C. and wherein, subsequent to said reaction, there is precipitative purification from ethyl acetate of benzyloxycarbonyl-His--D--Trp--Ala--Trp--D--Phe--Lys(Boc)--NH.sub.2 under neutral or alkaline conditions.
- 11. A method according to claim 9 which additionally involves treatment of the peptide product, benzyloxycarbonyl-His--D--Trp--Ala--Trp--D--Phe--Lys--(Boc)--NH.sub.2, under reductive conditions and under acidic conditions to form a peptide of the formula His--D--Trp--Ala--Trp--D--Phe--Lys--NH.sub.2.
- 12. A method of claim 8 wherein a racemization inhibitor is also added to the solvent.
- 13. A method of claim 12 wherein the racemization inhibitor is 1-hydroxy-benzotriazole or N-hydroxysuccinimide.
- 14. The method for forming a substantially pure protected peptide of the formula A.sub.2 --A.sub.3 --A.sub.4 --A.sub.5 --A.sub.6 --A.sub.7 which comprises:
- reacting a peptide fragment of the formula
- X--A.sub.2 --Y
- with a peptide of the formula
- U--V--W
- in a polar solvent which solubilizes the two fragments, in the presence of a dehydrating agent and activating agent under conditions sufficient for the fragments to react,
- wherein said U--V--W is 2NH--A.sub.5 --A.sub.6 --A.sub.7 (protecting group)--NH.sub.2 and further wherein A.sub.5 is Trp, A.sub.6 is DPhe and A.sub.7 is Lys, and
- wherein X--A.sub.2 --Y is (protecting group)--A.sub.2 --A3--A4--OH
- wherein A2 is His, A.sub.3 is DTrp, DPhe, D.sup..beta. Nal or D.sup..alpha. Nal, and A.sub.4 is Ala, and said substantially pure protected peptide is separated by precipitation.
- 15. The method of claim 14 wherein X--A.sub.2 --Y is CBZ--His--DTrp--Ala.
- 16. A method of claim 14 wherein a racemization inhibitor is added to the solvent.
- 17. A method of claim 16 wherein said racemization inhibitor is 1-Hydroxybenzotriazole or N-Hydroxysuccinimide.
Parent Case Info
This is a continuation of copending application Ser. No. 07/558,121 filed on Jul. 24, 1990 now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4774319 |
Ono et al. |
Sep 1988 |
|
4880778 |
Bowers et al. |
Nov 1989 |
|
Foreign Referenced Citations (3)
Number |
Date |
Country |
WO8907110 |
Aug 1989 |
WOX |
WO8907111 |
Aug 1989 |
WOX |
WO8910933 |
Nov 1989 |
WOX |
Non-Patent Literature Citations (3)
Entry |
Gross & Meinhofer, The Peptides, vol. 2 (Academic Press, 1980) Pp. 287-289. |
M. Bodanszky, Principles of Peptide Syntheses (Springer-Verlag (1984) 208-210. |
M. Bodanszky, Intl. J. Pept. Prot. Res. vol. 25 (1985) 449-474. |
Continuations (1)
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Number |
Date |
Country |
Parent |
558121 |
Jul 1990 |
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