HHC under scrutiny: chemical structure

07. 03. 2024

Where did the hydrocannabinol come from?

The journey of HHC from its first mention to the present is quite long. The discovery of hexahydrocannabinol occurred as early as 1944, when American chemist Roger Adams added a hydrogen molecule to delta 9-THC, thus converting THC to HHC by hydrogenation.

It was not until many years later, in 1979, that HHC was first discovered in the cannabis plant itself. The fact is that it is only present in such small quantities that extracting the compound would be very difficult, especially financially. Therefore, hexahydrocannabinol is produced exclusively in the laboratory using various methods, nowadays without the need to use THC itself, which is problematic from a legislative point of view, as a starting material. In view of the above, we consider HHC to be a semi-synthetic cannabinoid.

There are 4 basic types of HHC:

9-OH-HHC (9α-hydroxyhexahydrocannabinol)

7-OH-HHC (7-hydroxyhexahydrocannabinol)

Cannabiripsol [(6aR,9S,10S,10aR)-9 = 10-dihydroxyhexahydrocannabinol]

HU243 [11-hydroxy-3=(1′,1′-dimethylheptyl)hexahydrocannabinol]

There is no HHC like HHC

Briefly about HHC and the discovery of its presence in cannabis in 1979. At that time, one particular form of HHC was discovered in cannabis, namely cannabiripsol [(6aR, 9S, 10S, 10aR) 9,10-dihydroxy-hexahydrocannabinol]. A full 36 years later, in 2015, other cannabis compounds were discovered and the occurrence of cannabiripsol (HHC) in cannabis was officially confirmed. A year later (2016), when examining the cannabis sativa plant (cannabis seed), they identified a number of other HHC isomers (these were 9α-hydroxyhexahydrocannabinol / 7-oxo-9α-hydroxyhexa-hydrocannabinol / 10α-hydroxyhexahydrocannabinol / 10αR-hydroxyhexahydrocannabinol / Δ9-THC aldehyde A / 8-oxo-Δ9-THC / 10α-hydroxy-10-oxo-Δ8-THC / 9α-hydroxy-10-oxo-Δ6a10a-THC / 1S-hydroxycannabinol).

Chemical structure of HHC

There are currently several analogues of the hydrogenated form of THC (i.e. HHC) on the market and the number is expected to continue to expand. In fact, there are two variables that can be modified to produce another isomer.

• Adding a double bond to the upper ring structure of the THC molecule
• Modification of the length of the side chain that originates from the lower benzene ring of the THC molecule

HHC belongs to the first group, it is characterized by the absence of a double bond on the upper structure of THC. However, its minor transformations can also lead to other cannabinoids:

• Double bond on the tenth carbon - delta 10-THC
• Double bond on the ninth carbon - delta 9-THC
• Double bond on the eighth carbon - delta 8-THC
• Double bond on the fifth or seventh carbon - delta 7-THC
• Maximum number of double bonds - CBN
• Without double bonds - HHC

HHC versus THC

As can be seen from the list above, HHC could be described as THC without double bonds. This is because they have all been replaced by hydrogen during hydrogenation. However, the effects are similar - about half the potency of HHC (claims based on user reviews) and closest to those of delta 8-THC.

(R)-HHC versus (S)-HHC

Some laboratory reports distinguish two different stereoisomers of HHC. These are the same compounds, i.e. with the same structure, but they differ in their three-dimensional shape. The arrangement of the molecules in space then affects their ability to bind to endocannabinoid receptors in the human body.

While (R)-HHC is considered an active stereoisomer, (S)-HHC is an inactive stereoisomer. The active (R)-HHC can be concentrated (to form a so-called racemic mixture). However, this process is very complex and in most cases so expensive that it is not worthwhile. Thus, most HHC products you will find on the market contain approximately equal proportions of (R)- and (S)-HHC (50:50).

Summary

The chemical structure of HHC is complex and only a step away from THC. The similarity is not only in the structure but also in the effects of both substances. This is why it is one of the most popular cannabinoids today. Production has long since ceased to be tied to THC, but the similarity to THC cannot be denied.