WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 206925

CAS#: 4657-20-9

Description: Quadrosilan, also known as Cisobitan and KABI-1774, is a synthetic, nonsteroidal estrogen that was developed in the 1970s and that is or has been used as an antigonadotropic agent in the treatment of prostate cancer. It is an organosilicon compound, and is also known as 2,6-cisdiphenylhexamethylcyclotetrasiloxane. Quadrosilan has estrogenic activity equivalent to that of estradiol, and can produce feminization and gynecomastia as side effects in male patients.

Price and Availability




Quadrosilan is not in stock, may be available through custom synthesis. For cost-effective reason, minimum 1 gram order is requested. The product will be characterized by NMR, HPLC and MS analysis. Purity (HPLC) is usually >98%. CoA, QC data, MSDS will be provided when product is successfully made. The estimated lead time is 2-3 months. Please send email to sales@medkoo.com to inquire quote.

Chemical Structure


Theoretical Analysis

MedKoo Cat#: 206925
Name: Quadrosilan
CAS#: 4657-20-9
Chemical Formula: C18H28O4Si4
Exact Mass: 420.1065
Molecular Weight: 420.758
Elemental Analysis: C, 51.38; H, 6.71; O, 15.21; Si, 26.70

Synonym: Quadrosilan, Cisobitan; KABI-1774; KABI 1774; KABI1774.

IUPAC/Chemical Name: 2,2,4,6,6,8-hexamethyl-4,8-diphenyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane


InChi Code: InChI=1S/C18H28O4Si4/c1-23(2)19-25(5,17-13-9-7-10-14-17)21-24(3,4)22-26(6,20-23)18-15-11-8-12-16-18/h7-16H,1-6H3

SMILES Code: C[Si]1(C2=CC=CC=C2)O[Si](C)(C)O[Si](C3=CC=CC=C3)(C)O[Si](C)(C)O1

Technical Data

Solid powder

>98% (or refer to the Certificate of Analysis)

Shipping Condition:
Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition:
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Soluble in DMSO

Shelf Life:
>2 years if stored properly

Drug Formulation:
This drug may be formulated in DMSO

Stock Solution Storage:
0 - 4 C for short term (days to weeks), or -20 C for long term (months).

Harmonized System Code:


1: Alfthan O, Andersson L, Esposti PL, Fosså SD, Gammelgaard PA, Gjöres JE, Isacson S, Rasmussen F, Ruutu M, von Schreeb T, Setterberg G, Strandell P, Strindberg B. Cisobitan in treatment of prostatic cancer. A prospective controlled multicentre study. Scand J Urol Nephrol. 1983;17(1):37-43. PubMed PMID: 6346476.

2: Collste L, Berlin T, von Garrelts B, Granberg I, Lewander R. Clinical trial of a new antigonadotropic substance, 2,6-cis-diphenylhexamethylcyclotetrasiloxane, in cancer of the prostate. A pilot study. Eur Urol. 1981;7(2):85-8. PubMed PMID: 7461008.

3: Sundwall A. Cisobitan--a new drug with anti-gonadotropic and anti-androgenic properties. Pharmacological effects. Scand J Urol Nephrol Suppl. 1980;55:121-5. PubMed PMID: 6938014.

4: Albanus L, Björklund NE, Gustafsson B, Jönsson M. Forty days oral toxicity of 2,6-cis-diphenylhexamethylcyclotetrasiloxane (KABI 1774)in beagle dogs with special reference to effects on the male reproductive system. Acta Pharmacol Toxicol (Copenh). 1975;36(Suppl 3):93-130. PubMed PMID: 1080338.

5: Nicander L. Changes produced in the male genital organs of rabbits and dogs by 2,6-cis-diphenylhexamethylcyclotetrasiloxane (KABI 1774). Acta Pharmacol Toxicol (Copenh). 1975;36(Suppl 3):40-54. PubMed PMID: 1080333.

6: Schmiterlöw CG, Sjögren C. The distribution of 14-C labelled KABI 1774. Acta Pharmacol Toxicol (Copenh). 1975;36(Suppl 3):131-8. PubMed PMID: 1080328.

7: Nicander L. The effects on the male genital organs and dogs of a new antifertility compound KABI 1774. J Reprod Fertil. 1972 Dec;31(3):517-8. PubMed PMID: 4653473.