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Heterocyclic building blocks

Happ

Also known as 8-Aza-7-deazaguanine, PPG nucleoside, 6-amino-1-(4-hydroxy-5-hydroxymethyl-tetrahydrofuran-2-yl)-1,5-dihydropyrazolo(3,4-d)pyrimidin-4-one

CAS 2537-04-4Formula C5H5N5OMolar mass 151.13 g/molEC 985-577-5
GHS signal word: Danger. Pictograms: Corrosive, Harmful or irritant 1 supplier listed
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Happ chemical structure, C5H5N5O, CAS 2537-04-4
2D chemical structure

Key facts

What buyers check first

All properties
CAS number
2537-04-4
Formula
C5H5N5O
Molar mass
151.13 g/mol
EC number
985-577-5
HS code
293359
Category
Heterocyclic building blocks

What is Happ?

Plain description, key identifiers and synonyms

Happ is a chemical substance with the molecular formula C5H5N5O and a molar mass of 151.13 g/mol. Its CAS registry number is 2537-04-4. The IUPAC name is 6-amino-1,5-dihydropyrazolo[5,4-d]pyrimidin-4-one.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
6-amino-1,5-dihydropyrazolo[5,4-d]pyrimidin-4-one
CAS number
2537-04-4 CAS number cross-checked
EC number
985-577-5
Molecular formula
C5H5N5O
UNII
5UP5FE6923
InChIKey
BZUZJVLPAKJIBP-UHFFFAOYSA-N
InChI
InChI=1S/C5H5N5O/c6-5-8-3-2(1-7-10-3)4(11)9-5/h1H,(H4,6,7,8,9,10,11)
SMILES (canonical and isomeric)
C1=NNC2=C1C(=O)NC(=N2)N

Synonyms

  • 8-Aza-7-deazaguanine
  • PPG nucleoside
  • 6-amino-1-(4-hydroxy-5-hydroxymethyl-tetrahydrofuran-2-yl)-1,5-dihydropyrazolo(3,4-d)pyrimidin-4-one
  • 6-Amino-1H-pyrazolo[3,4-d]pyrimidin-4(7H)-one
  • 6-amino-1,5-dihydro-4h-pyrazolo[3,4-d]pyrimidin-4-one
  • 6-amino-1H-pyrazolo[3,4-d]pyrimidin-4-ol
  • 4-Hydroxy-6-aminopyrazolo[3,4-d]pyrimidine
  • 4-Hydroxy-6-aminopyrazolo(3,4-d)pyrimidine
  • 1H-Pyrazolo[3, 6-amino-
  • 6-amino-1,2-dihydropyrazolo[3,4-d]pyrimidin-4-one
  • 4-Oxo-6-aminopyrazolo[3,4-d]pyrimidine
  • 4H-Pyrazolo[3, 6-amino-1,5-dihydro-
  • 1H-Pyrazolo[3,4-d]pyrimidin-4-ol, 6-amino-
  • 6-amino-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one
  • 4H-Pyrazolo[3,4-d]pyrimidin-4-one, 6-amino-1,5-dihydro-
  • 6-Amino-1,2-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one
  • 2,2,4-trimethyl-2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one
  • 2H,6H-pyrimido[2,1-b][1,3]thiazin-6-one, 2,2,4-trimethyl-

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

No measured properties are recorded for this substance yet. Ask suppliers for a technical data sheet.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
151.13 g/molcalc.
Exact mass
151.0494 Dacalc.
LogP (octanol/water)
-0.77calc.
Topological polar surface area
100.5 Ųcalc.
Hydrogen bond donors
3calc.
Hydrogen bond acceptors
4calc.
Rotatable bonds
0calc.
Heavy atoms
11calc.
Rings
2calc.
Aromatic rings
2calc.
Fraction sp3 carbons
0calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, O=c1[nH]cnc2[nH]ncc12

O=c1[nH]cnc2[nH]ncc12

2 rings, 10 atoms, the Allopurinol ring system.

279 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS05: Corrosive
Corrosive
GHS07: Harmful or irritant
Harmful or irritant

Hazard statements

  • H302Harmful if swallowed.
  • H315Causes skin irritation.
  • H318Causes serious eye damage.
  • H335May cause respiratory irritation.
Precautionary statements (19)
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P301 + P317If swallowed: Get medical help.
  • P302 + P352If on skin: Wash with plenty of water.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P354 + P338If in eyes: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P317Get medical help.
  • P319Get medical help if you feel unwell.
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P332 + P317If skin irritation occurs: Get medical help.
  • P362 + P364Take off contaminated clothing. And wash it before reuse.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Happ suppliers

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Where suppliers are based

1 supplier in 1 country

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Happ price

Indicative price range per kg from live supplier offers

No published prices right now

Suppliers quote this chemical on request. Send one free request and compare quotes side by side.

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Uses and applications

What the substance is used for, by industry and function

Regulatory status

Inventories, regulations and trade controls that list this substance

No regulatory list memberships are recorded for this substance yet. Always check the rules of the importing and exporting country before trade.

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Happ is traded under.

HS 2933.59Indicative HS code

Compounds containing a pyrimidine ring (whether or not hydrogenated) or piperazine ring, other

World exports in 2024
$18.4B
+10.5% vs 2023, imports $24.8B
2019 to 2024
Top exporters
  1. Ireland43.6%
  2. Switzerland * partner reported26.3%
  3. China7.9%
Top importers
  1. Slovenia30.3%
  2. United States30.1%
  3. Germany15.3%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Happ is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Happ, based on the data on this page

What is Happ?

Happ is a chemical substance with the molecular formula C5H5N5O and a molar mass of 151.13 g/mol. Its CAS registry number is 2537-04-4. The IUPAC name is 6-amino-1,5-dihydropyrazolo[5,4-d]pyrimidin-4-one.

What is the CAS number of Happ?

The CAS registry number of Happ is 2537-04-4.

What is the molecular formula and weight of Happ?

The molecular formula of Happ is C5H5N5O and its molar mass is 151.13 g/mol.

What is Happ used for?

Known uses and roles of Happ include building blocks in research and laboratory and screening compounds in research and laboratory.

Is Happ hazardous?

Happ carries the GHS signal word "Danger". Main hazards: harmful if swallowed, causes skin irritation, causes serious eye damage. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Happ?

Happ is usually classified under HS code 293359 (Compounds containing a pyrimidine ring (whether or not hydrogenated) or piperazine ring…). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Happ?

CompoundList lists 1 supplier of Happ in China. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of Happ?

Suppliers quote Happ on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Happ

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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