Efficient synthesis of pyropheophorbide a and its derivatives
First Claim
Patent Images
1. A process for the preparation of methyl pheophorbide-a, comprising treating chorin e6 trimethyl ester with a base in an aromatic solvent having a boiling point at least as high as 144°
- C., the boiling point of 2,6-lutidine.
3 Assignments
0 Petitions
Accused Products
Abstract
A process for the preparation of pyropheophorbide a and its derivatives, including 3-devinyl-3-(1′-hexyloxy)ethyl-pyropheophorbide-a, otherwise known as HPPH, is provided. The process involves treating chlorin e6, in the form of its trimethyl ester, with a base, followed by heating to give pyropheophorbide a, which is converted to HPPH by treatment with acid, followed by hexyl alcohol under basic conditions.
-
Citations
11 Claims
-
1. A process for the preparation of methyl pheophorbide-a, comprising treating chorin e6 trimethyl ester with a base in an aromatic solvent having a boiling point at least as high as 144°
- C., the boiling point of 2,6-lutidine.
-
2. A process for the preparation of methyl pheophorbide-a, comprising:
-
(a) treating chorin e6 trimethyl ester with a base in an aromatic solvent having a boiling point at least as high as 144°
C., the boiling point of 2,6-lutidine to give methyl pheophorbide-a; and(b) without isolating the methyl pheophobide-a from the resulting reaction mixture, heating the methyl pheophorbide-a to a temperature sufficient to effect decarboxylation and saponification of the methyl pheophorbide-a. - View Dependent Claims (11)
-
-
3. A process for the preparation of ether analogs of pyropheophorbide-a comprising:
-
(a) treating chorin e6 trimethyl ester with a base in an aromatic solvent having a boiling point at least as high as 144°
C., the boiling point of 2,6-lutidine to give methyl pheophorbide-a;(b) without isolating the methyl pheophobide-a from the resulting reaction mixture, heating the methyl pheophorbide-a to a temperature sufficient to effect decarboxylation and saponification of the methyl pheophorbide-a to give pheophorbide-a; and (c) treating the pyropheophorbide-a with an acid, followed by an alcohol under basic conditions to effect addition of the alcohol across a vinyl group. - View Dependent Claims (4)
-
-
5. A process for the preparation of purpurin-18, comprising:
(a) treating chlorin e6 trimethyl ester with a base in an aromatic solvent in the presence of air to give purpurin-18 having a —
CH2CH2COOH group.
-
6. A process for the preparation of purpurinimides, comprising:
-
(a) treating chlorin e6 trimethyl ester with a base in an aromatic solvent in the presence of air to give purpurin-18 having a —
CH2CH2COOH group;(b) esterifying the —
CH2CH2COOH group to obtain purpurin-18 ester; and(c) treating the esterified purpurin-18 with a primary amine.
-
-
7. A process for the preparation of ether analogs of purpurinimides, comprising:
-
(a) treating chlorin e6 trimethyl ester with a base in an aromatic solvent in the presence of air to give purpurin-18 having a —
CH2CH2COOH group;(b) esterifying the —
CH2CH2COOH group to obtain purpurin-18 ester;(c) treating the esterified purpurin-18 ester with a primary amine; and (d) treating the resulting purpurinimide with an acid, followed by an alcohol under basic conditions.
-
-
8. A process for the preparation of purpurin-18 ester, comprising:
-
(a) treating chlorin e6 trimethyl ester with a base in an aromatic solvent in the presence of air to give purpurin-18 having a —
CH2CH2COOH group; and(b) esterifying the —
CH2CH2COOH group. - View Dependent Claims (9, 10)
-
Specification