World largest library of tangible building blocks

In 2007 Enamine Ltd and UORSY (Ukrorgsyntez Ltd) launched a joint project in order to establish a systematic chemically validated approach to synthesis of "in-stock-tomorrow" building blocks that consist of up to 21 heavy atoms and therefore can be used in medicinal chemistry and drug discovery. The average values for number of heavy atoms, MW and cLogP of the tangible building blocks are 18.3, 272 and 2.3, respectively. Full database (20 556 947 structures) and other relevant data including prices can be found at the library download page. The golden set of tangible building blocks (4 721 351 structures, containing up to 16 heavy atoms) have also been posted at Accelrys® Available Chemicals Directory. These databases are updated at least two times a year.

The main chemical classes of tangible building blocks are listed in the table below.

Type of Building Blocks Number of structures
Primary and Secondary Amines 4 484 000
Carboxylic Acids 1 009 000
Amino Acids 191 000
Alkylating and Arylating Agents 679 000
Sulfonyl Chlorides 26 000
Aldehydes and Ketones 317 000
Alkyl- and Arylhydrazines 43 000
Alcohols 852 000
Phenols 135 000
Thiols 27 000
Amidoximes and Amidines 118 000
Aryl bromides and Aryl iodides 743 000
Boronic acids 7 000
Alkyl- and Arylazides 7 600
Terminal acetylenes 34 000

Rigorously validated chemical procedures ensure high feasibility and cost effectiveness of tangible building blocks and fragments. About 8 500 building blocks were synthesized in 2009 with lead time of 4-6 weeks and feasibility of 80%.  Over 4 000 of these compounds were selected from the database of tangible building blocks and ordered by pharma and biotech companies worldwide at fixed prices ranging from 200 to 800 € per gram. Weekly progress reports on the synthesis of the ordered tangible building blocks and fragments are provided to the customers.

Screening collection

Screening collection

We are proud to offer the world’s largest collection of screening compounds for the biological screening. Our screening collection currently contains 2 744 501 low molecular weight organic compounds. Synthesis of such immense number of diverse and distinct compounds in significant amount (typically 150 mg is in stock) was enabled owing to the early focus of the company on development of its own building block inventory.

Screening Collection

All Enamine screening compounds are grouped into several collections: HTS, Advanced, Premium and Functional.

HTS Collection, Z1004213698

HTS Collection
MW 370.4
ClogP 3.31

Advanced Collection, Z1024897770

Advanced Collection
MW 338.4
ClogP 2.73

Premium Collection, Z1139301883

Premium Collection
MW 348.4
ClogP -0.32

Targeted and Focused Libraries

In order to provide more efficient way for navigating among millions of screening compounds offered by Enamine, we have carefully designed a set of diversified Targeted and Focused libraries suitable to address a wide range of research needs. We put our efforts, expertise, and imagination to facilitate your search.

Quality Control and Packaging

All Enamine compounds have undergone rigorous quality control with LCMS and/or 1H NMR to meet requirement of 90% purity. The compounds are stored as dry powders and a part of collection (around 250K compounds) have been put in solutions to assure smooth handling of oily and sticky compounds.

Selected Enamine compounds can be delivered in any custom format including vials, 384- and 1536-well plates.

Building Blocks

Building Blocks

Enamine designs, develops and synthesizes chemical reagents, scaffolds and intermediates widely known as building blocks. They are convenient for using in medicinal chemistry and synthesis of combinatorial compound libraries.

Our catalogue currently contains 1 011 199 building blocks including 225 000 compounds in stock, which can be delivered within 1-7 days from our global logistics centers in the USA and Europe, and via our official distributors in Asia and Oceania. To date, Enamine collection is the largest and most abundant single source of medchem building blocks in the world

Key Facts:

  • Most building blocks are available from stock in 1-5 g amounts.
  • At you can find up-to-date prices, availability, and lead times for most of the building blocks in stock and for synthesis.
  • All of our chemical building blocks undergo extensive quality control by NMR and LC-MS, and purity is guaranteed to be over 95%.
  • You can download MSDS and CoA for most of the building blocks here.

Below is a diagram showing stock composition by classes of building blocks:

Building Blocks by functions

MedChem Highlights

MADE Building Blocks

You can browse and purchase our building blocks at our online shop EnamineStore. There you will get up-to-date price, availability, and lead time information.

Each month our catalogue is enriched with over 1 500 new building blocks. You can be among the first to discover these innovative molecules by subscribing to our Catalogue Update Letters. Each of these monthly updates will bring you around 60 carefully selected, most interesting structures of building blocks that are available for immediate purchase from our stock.


Enamine offers world class service in chemical synthesis of a wide variety of organic compounds on the milligram to kilogram scale at competitive price.


We offer comprehensive support in developing your hit compounds. Naturally such programs are realised most efficiently when biological actives originate from our screening collection. However, even if the hit compounds are from the collections of other vendors lead identification and optimization projects can proceed most productively in our hands. Sometimes for this we only need to synthesize first examples of the given chemical series and validate synthesis route.


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