16-Dehydropregnenolone acetate

Names
IUPAC name 20-Oxopregna-5,16-dien-3β-yl acetate
Systematic IUPAC name (3aS,3bR,7S,9aR,9bS,11aS)-1-Acetyl-9a,11a-dimethyl-3a,3b,4,6,7,8,9,9a,9b,10,11,11a-dodecahydro-3H-cyclopenta[a]phenanthren-7-yl acetate
Other names 16-DPA; 5,16-Pregnadien-3β-ol-20-one acetate; 3β-Hydroxy-5,16-pregnadien-20-one acetate; 3β-Acetoxy-5,16-pregnadien-20-one
Identifiers
CAS Number	979-02-2
ChEBI	CHEBI:34163
ChEMBL	ChEMBL1761683
ChemSpider	83823
ECHA InfoCard	100.012.326
EC Number	213-558-7
KEGG	C14503
PubChem CID	92855
UNII	832VMW7ZGC Y
CompTox Dashboard (EPA)	DTXSID8057857
InChI InChI=1S/C23H32O3/c1-14(24)19-7-8-20-18-6-5-16-13-17(26-15(2)25)9-11-22(16,3)21(18)10-12-23(19,20)4/h5,7,17-18,20-21H,6,8-13H2,1-4H3/t17-,18-,20-,21-,22-,23+/m0/s1 Key: MZWRIOUCMXPLKV-VMNVZBNLSA-N
Properties
Chemical formula	C23H32O3
Molar mass	356.506 g·mol−1
Appearance	White crystalline powder
Melting point	171–172 °C (340–342 °F; 444–445 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

16-Dehydropregnenolone acetate (16-DPA) is a chemical compound used as an intermediate or synthon in the production of many semisynthetic steroids. As 7-ACA is for cephalosporins and 6-APA is for penicillins, 16-DPA is for steroids. While it is not easy to synthesize, it is a convenient intermediate which can be made from other more available materials, and which can then be modified to produce the desired target compound.

16-DPA can be produced from a variety of steroidal sapogenins. Industrially useful sources are diosgenin in mexican yams^[1][2] and solasodine from certain nightshades. These two sapogenins can be used in a one-pot synthesis.^[3] Solanidine in potato greens, an alkaloid sapogenin, is also a key source material.^[4]

Compounds derived from 16-DPA include:

• Corticosteroids (mainly of a C22 pregnane backbone): hydrocortisone*, betamethasone*, dexamethasone*, beclometasone*, fluticasone, and prednicarbate;^[5]
• Progestogen (mainly of a C22 pregnane backbone): pregnenolone, progesterone*,^[6] various synthetic derivatives such as medroxyprogesterone acetate* and levonorgestrel*;
• Androgens (mainly of a C19 androstane, 17-keto backbone): testosterone*^[7] and esters, various synthetic derivatives;
• Estrogens (mainly of a C18 estrane, 17-hydroxy backbone): estradiol^[7] and esters such as estradiol cypionate*, various synthetic derivatives such as ethinylestradiol*.

Those marked with a * appear on the WHO Model List of Essential Medicines, some as part of a compound medication. The list is by no means complete due to the central role of 16-DPA in steroid production.

There are no current medical uses of 16-DPA. Studies in male hamsters show that the related chemical 16-DHP acts as an farnesoid X receptor (FXR) antagonist, consequently up-regulating CYP7A1 and lowering serum cholesterol. The CSIR-CDRI holds a patent over 16-DHP for prospective lipid-lowering use.^[8]

Production of substantial quantities of steroids was not achieved until the Marker degradation in the late 1930s, a synthesis route converting diosgenin into the related compound 16-dehydropregnenolone (16-DP or 16-DHP). This reaction established Mexico as a world center of steroid production.^[9] 16-DPA was produced in a variant of Marker degradation published in 1940.^[6]

The earliest PubChem patent record for 16-DPA is US2656364A of 1951, describing its conversion into 17-ketosteroids.^[7]

• Mexican barbasco trade