Azadirachtin, a chemical compound belonging to the limonoid

Limonoid

Limonoids are phytochemicals, abundant in citrus fruit and other plants of the families Rutaceae and Meliaceae. Currently limonoids are under investigation for a wide variety of therapeutic effects such as antiviral or Viricide, antifungal, antibacterial, antineoplastic and antimalarial...

 group, is a secondary metabolite

Secondary metabolite

Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of an organism. Unlike primary metabolites, absence of secondary metabolities does not result in immediate death, but rather in long-term impairment of the organism's...

 present in neem

Neem

Azadirachta indica is a tree in the mahogany family Meliaceae. It is one of two species in the genus Azadirachta, and is native to India growing in tropical and semi-tropical regions. Its fruits and seeds are the source of neem oil...

 seeds. It is a highly oxidized tetranortriterpenoid

Tetranortriterpenoid

The tetranortriterpenoid class of chemical compounds most noted for the chemical azadirachtin, extracted from the neem tree that displays insecticidal properties...

 which boasts a plethora of oxygen functionality, comprising an enol ether

Enol ether

An enol ether is an alkene with an alkoxy substituent. The general structure is R_1R_2C=CR_3-O-R_4 with R an alkyl or an aryl group. Enol ethers and enamines are so-called activated alkenes or electron rich alkenes because the oxygen atom donates electrons to the double bond by forming a resonance...

, acetal, hemiacetal

Hemiacetal

Hemiacetals and hemiketals are compounds that are derived from aldehydes and ketones respectively. The Greek word hèmi means half...

, and tetra-substituted oxirane as well as a variety of carboxylic esters.
Azadirachtin has a complex molecular structure, and as a result the first synthesis was not published for over 22 years after the compound's discovery.