5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one

Also known as: Sildenafil lactam impurity, UK-088800, 5-(2-ethoxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one, 7H-pyrazolo[4,3-d]pyrimidin-7-one, 5-(2-ethoxyphenyl)-1,6-dihydro-1-methyl-3-propyl-, 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one, 5-(2-ethoxyphenyl)-1-methyl-3-propyl-4H-pyrazolo[4,3-d]pyrimidin-7-one

5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (CAS 139756-21-1) is a compound in the Pharma Intermediates category listed in the Jingsj chemical database. It has the molecular formula C17H20N4O2 and a molecular weight of 312.366 g/mol. Key properties include a melting point of 141-145ºC(lit.), a boiling point of 504ºC at 760 mmHg, a density of 1.3±0.1 g/cm3 and a flash point of 258.6ºC. It is classified under GHS with signal word Warning and hazard statements H315 — Causes skin irritation, H319 — Causes serious eye irritation and H335 — May cause respiratory irritation. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 139756-21-1
Jingsj CID: J-1971442-2
Molecular Formula: C₁₇H₂₀N₄O₂
Molecular Weight: 312.366 g/mol
Category: Pharma Intermediates
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	141-145ºC(lit.)
Boiling Point	504ºC at 760 mmHg
Density	1.3±0.1 g/cm3
Flash Point	258.6ºC
Exact Mass	312.158630
PSA	72.80000
LogP	2.38
Vapor Pressure	2.75E-10mmHg at 25°C
Refractive Index	1.632

GHS Safety & Compliance

IrritantSignal word: Warning

H315 — Causes skin irritation
H319 — Causes serious eye irritation
H335 — May cause respiratory irritation

Activity & Biological Data

Target	PDE5:5 nM (IC50) PDE1:300 nM (IC50)

Customs & Trade Information

HS Code	2933990090
Summary	2933990090. heterocyclic compounds with nitrogen hetero-atom(s) only. VAT:17.0%. Tax rebate rate:13.0%. . MFN tariff:6.5%. General tariff:20.0%

Frequently Asked Questions

What is the CAS number of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one?

The CAS number of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one is 139756-21-1.

What are the molecular formula and molecular weight of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one?

5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one has molecular formula C17H20N4O2 and molecular weight 312.366 g/mol.

Is 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one hazardous?

5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one has GHS signal word Warning and hazard statements H315 — Causes skin irritation; H319 — Causes serious eye irritation; H335 — May cause respiratory irritation.

What are the upstream and downstream products of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one?

For 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one, Upstream Products: 4-[(2-Ethoxybenzoyl)amino]-1-methyl-3-propyl-1H-pyrazole-5-carboxamide, 2-Ethoxybenzaldehyde, 4-Amino-1-methyl-3-propyl-1H-pyrazole-5-carboxamide; Downstream Products: Norneosildenafil, Hydroxyhomosildenafil, 4-Ethoxy-3-(1-methyl-7-oxo-3-propyl-6,7-dihydro-1H-pyrazolo[4,3-d]pyrimidin-5-yl)benzene-1-sulfonyl chloride.

Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.

Last updated: 8/21/2026

How to cite: Jingsj. "5-(2-ethoxyphenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (CAS 139756-21-1)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-1971442-2 (accessed 2026-11-09).

Data for reference only; verify product details with suppliers before purchase.