# CARBORANYL PORPHYRINS FOR CANCER RADIOTHERAPY

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 1987 · $84,301

## Abstract

The synthesis of a wide variety of water-soluble porphyrins containing the
o-carborane group, 1,2-B10C2H12, is proposed using six different synthetic
organic methodolgies.  These include (I) Rothemund condensations of
carboranyl aldehydes, (II) carboranyl-amido-linked porphyrins from
meso-tetra (aminophenyl)porphyrins, (III) Rothemund condensations of
carboranylbenzaldehydes, (IV) billadienes-ac condensations with carboranyl
aldehydes, (V) nucleophilic and elctrophilic reactions of carborane
derivatives on natural porphyrins or their derivatives, and (IV) the total
synthesis Beta-carboranyl porphyrins.  In classes (I)-(IV) water solubility
is to be achieved by the subsequent addition of four different
water-solubilizing groups, while in (IV) and (V) it is achieved by the
Beta-pyrole propionic acid groups of natural porphyrins.  Biomedical
evaluation of these compounds will include toxicological and
tumor-localization studies carried out by a group at Brookhaven National
Laboratories.  In suitable cases this will be followed by neutron capture
therapy experimental trials in animals.  No funds are requested for such
testing since the BNL group is already fully supported by the Department of
Energy to perform this testing.  Protocols for these studies are
described.  The over-all objectives of the proposed work is to prepare
boronated porphyrins which will selectively accumulate in tumor cells.  The
use of boron compounds in the treatment of cancer is based on the unique
ability of non-radioactive 10B to absorb thermal (low energy) neutrons.
The prompt nuclear reactions which occur on thermal neutron absorption
deliver a dose of nearly 2.8 NEV only in the vicinity of boron-containing
cells since the nuclear fragments produced (alpha particles and lithium
atoms) travel only 10-15 um.  Porphyrins of both natural and synthetic
origin have been shown by a number of investigators to accumulate in
neoplastic tissue.  Such localization forms the basis for current clinical
phototherapy of a variety of concerns.  Preliminary work by the author has
resulted in the synthesis of several novel carborane porphyrins.  One of
these is found to localize in the malanoma mouse model system and used for
preliminary screening at BNL in therapeutically significant amounts and
over a time course significantly better than Na2B12H11SH, the borane in
current clinical use in Japan.  In light of these encouraging results,
funds are requested to support a significant broadening of the synthetic
chemical effort at UCSF.

## Key facts

- **NIH application ID:** 3175947
- **Project number:** 5R01CA037961-03
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **SAM.gov UEI:** KMH5K9V7S518
- **Principal Investigator:** STEPHEN B KAHL
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $84,301
- **Award type:** 5
- **Project period:** 1985-07-01 → 1988-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3175947

## Citation

> US National Institutes of Health, RePORTER application 3175947, CARBORANYL PORPHYRINS FOR CANCER RADIOTHERAPY (5R01CA037961-03). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3175947. Licensed CC0.

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