# The Muni Metro Benzodioxole Ladder > The Muni Metro Benzodioxole Ladder is the family of MDMA-adjacent compounds in PIHKAL (Alexander Shulgin, 1991) built on the 1,3-benzodioxole ring — METHYL-J, METHYL-K, ETHYL-J, ETHYL-K and the… Canonical: https://wiki.soapbox.community/wiki/The_Muni_Metro_Benzodioxole_Ladder Section: Substances and pharmacology, Organic chemistry and synthesis Last updated: 2026-10-27 Publisher: Library of Ashurbanipal (Van Kush Family Research Institute), https://wiki.soapbox.community **The Muni Metro Benzodioxole Ladder** is the family of MDMA-adjacent compounds in *PIHKAL* (Alexander Shulgin, 1991) built on the 1,3-benzodioxole ring — METHYL-J, METHYL-K, ETHYL-J, ETHYL-K and the unexplored L-series — together with the N-substituted branch that grows off the same skeleton: MDPL, MDMP, MDBZ, MDCPM, MDHOET and METHYL-MMDA-2. The family is named after a streetcar system. It is organised along two axes — how long the carbon chain at the alpha-position is, and what is hung on the nitrogen — and both axes run out. Shulgin's own verdict on the first, at the pentane step, is "*The well appears to be running dry.*" ## The epistemic standing of this record Stated once. Everything below is **unblinded self-report** from Shulgin and a small research group, hand-escalated from sub-threshold doses, with no placebo arm and no blinding. In this family the problem has a particular shape, because the effects being judged are social and affective — warmth, intimacy, spontaneity — and the comparison standard is MDMA, a drug everyone in the room already knew well. A rating of "*lacking some of the spontaneity*" relative to a known drug, given by people who knew what they had taken, is a genuine observation and a weak measurement at the same time. Read it as testimony, not as data. ## Why "Muni Metro" The naming scheme is explained in the METHYL-J entry (128). The **Muni Metro** is the San Francisco Municipal Railway's underground streetcar network, whose lines connect out to the surface bus system, and whose lines are lettered: **J** Church, **K** Ingleside, **L** Taraval, **M** Ocean, **N** Judah. Shulgin borrowed the letters to index the length of the carbon chain hanging at the alpha-position of a 3,4-methylenedioxyphenyl compound. - **H** — no alpha-substituent at all: the plain phenethylamine, MDPEA, whose trivial name *homopiperonylamine* supplies the letter. - **I** — one carbon at the alpha-position: the amphetamines, already so thoroughly named that the letter is never used. MDA, MDMA and MDE are I, METHYL-I and ETHYL-I. - **J** — an alpha-ethyl group, two carbons. The corpus glosses the letter as deriving from "Jacobamine", after a chemist of that name. - **K** — three carbons, the propyl chain. - **L** — four carbons, the butyl chain; the end of the Taraval line. N-substitution is marked with a prefix: **METHYL-** and **ETHYL-**. So METHYL-J is the N-methyl compound with a two-carbon alpha chain — the molecule more usually written MBDB — and ETHYL-K is the N-ethyl compound with a three-carbon alpha chain. Shulgin's justification for slotting the amphetamines in as "I" is characteristically literal: "*It is quite obvious, that with one carbon atom lying on that alpha-position, you are precisely half-way between no carbons and two carbons*" — and I is half-way between H and J. For the wider naming system see Naming the Compounds Codes Greek Names and Shulgin Nomenclature. N-H N-methyl N-ethyl H (no α-C) MDPEA METHYL-H — I (1 C) MDA MDMA MDE J (2 C) J (BDB) METHYL-J ETHYL-J K (3 C) K METHYL-K ETHYL-K L (4 C) L METHYL-L ETHYL-L ← none assayed ## Walking up the alpha chain ### METHYL-J (entry 128) The one compound in the ladder with a real body of human data, and the one everything else is measured against. :"*An observer who was familiar with the outwardly apparent effects with groups experimenting with MDMA felt that, although most subjects commented favorably in their comparisons of METHYL-J with MDMA, there was lacking some of the spontaneity, the warmth, and the clear intimacy of the latter drug. The dosage range explored is remarkably tight, attesting to a consistency of response. The typical supplement used, if any, was 70 milligrams or less, just before the two hour point. This indicates a chronology similar to that of MDMA, and about two thirds the potency.*" Four separate facts are in that paragraph, and they are the most useful ones in the family: - **Potency**: about two thirds that of MDMA — so a given effect takes about half again as much material. - **Chronology**: similar to MDMA, inferred from where the supplement lands. A supplement taken "*just before the two hour point*" is a statement about when the plateau starts to fall away. - **Supplement size**: "*70 milligrams or less*". - **Variance**: low. "*The dosage range explored is remarkably tight, attesting to a consistency of response*" — which, in a corpus where inter-individual variance is usually the headline problem (see Idiosyncratic Responders Inter-Individual Variance and the Street Market), is itself a finding. What it does not have is MDMA's particular social signature. Adding one carbon at the alpha-position keeps the chronology, costs a third of the potency, and removes some of the "*spontaneity, the warmth, and the clear intimacy*". That is the exchange rate for the whole ladder. ### ETHYL-J (entry 77) The N-ethyl version of the same two-carbon chain, and the top of the explored range: "*And nothing higher has ever been looked at.*" The extrapolation is explicit and self-limiting: :"*If the analogy with the amphetamine counterparts (J with MDA, METHYL-J with MDMA, and this, with MDE) were to hold up (a drop of about a third in potency with the lengthening of the chain by a carbon atom), one might guess that this compound would be an interesting intoxicant, but probably not until you got up into the area at or above a 200 milligram dose. And that is a lot of chemical for the body to have to handle. Some day, maybe.*" **A drop of about a third per carbon** is the rule of thumb the family runs on, and the 200 mg figure is a prediction, never an observation. The clause that follows it is the one worth keeping: a predicted active dose that high is itself a reason not to go there, independent of what the compound might do. Milligram potency is a safety property, not just a convenience — the lower the active dose, the smaller the mass of unknown material a body has to clear. ### METHYL-K (entry 129) One more carbon, and the signal stops: :"*The well appears to be running dry, with a pentane chain as a basic skeleton. METHYL-J, at this level, was already showing a number of hints and clues, largely physical such as coldness in the feet and a slight mastoidal pressure, that activity was right around the corner. But METHYL-K gave no such hints.*" The method on display here is more interesting than the result. What Shulgin is tracking at sub-threshold doses is not mental effect but **physical prodrome** — coldness in the feet, pressure behind the ears — the small bodily signs that, in his experience, arrive one or two escalation steps before anything psychological does. Their *absence* is what closes the K line. The unmethylated homologue K (2-amino-1-(3,4-methylenedioxyphenyl)pentane) was made as a white crystalline solid, mp 202–203 °C, and reported "*in the comments only, as its human assaying had never even been initiated*". On the escalation protocol itself see The Shulgin Method Dose Escalation and the Research Group. ### ETHYL-K (entry 78) and the L-series ETHYL-K's commentary is two sentences long: "*And that is as high a dose as has apparently ever been tried with ETHYL-K.*" The hexane-chain L compounds were synthesised and characterised — L at mp 157–158 °C, METHYL-L at mp 139–141 °C, ETHYL-L prepared the same way with ethylamine — and then stopped: "*None of this series has yet been explored either as psychedelic or entactogenic materials.*" Three finished compounds, fully characterised, never tasted. They belong with the other stalled work in Shulgins Open Problems Compounds Left at the Aldehyde and Nitrostyrene Stage. ## The other axis: what goes on the nitrogen Changing the N-substituent on the MDA skeleton is cheaper synthetically than extending the alpha chain, and *PIHKAL* contains a long run of these. Almost all of them fail, and they fail for reasons that generalise. {| class="wikitable" ! Compound !! N-substituent !! What the corpus reports |- | **MDPL** (117) || propargyl (prop-2-ynyl) || Listed at >150 mg; the entry describes no effects at all and is given over entirely to nomenclature |- | **MDBZ** (103) || benzyl || "*Here too, there appears to be little if any activity in the N-benzyl analogue of MDA*" |- | **MDCPM** (104) || cyclopropylmethyl || "*The highest level tried was 10 milligrams, which showed no hint of activity*" |- | **MDHOET** (107) || 2-hydroxyethyl || "*Certainly not very active, if it is active at all*"; at several hundred mg, altered colour and depth perception, no euphoria, "*said to resemble a mild dose of ketamine*" |- | **MDMP** (113) || N-methyl, with a *gem*-dimethyl alpha (phentermine pattern) || "*Clearly not psychedelic at these modest levels*"; inactive as a serotonin releaser *in vitro*; "*one of several candidates for clinical use as a substitute for MDMA*" |- | **METHYL-MMDA-2** (131) || N-methyl, on the MMDA-2 ring || Parent active at 25–50 mg; "*The highest dose yet reported was 70 milligrams*", with no estimate of an active level |} **MDBZ** supplies the structural rule the rest of the table obeys. A benzylamine is not a phenethylamine, and the difference of one carbon is not a small one: :"*With most centrally active alkaloids, there is a two-carbon separation between the weak base that is called the aromatic ring, and the strong base that is called the nitrogen... If one carbon is removed, one has a benzylamine, and it is usually identified with an entirely different pharmacology, or is most often simply not active.*" His external evidence is fentanyl, where "*The replacement of the phenethyl group, attached to the nitrogen atom with a benzyl group, virtually eliminates its analgesic potency*". And his verdict on the synthetic chemist's favourite protecting group: "*The benzyl group is a good ally in the synthetic world of the organic chemist... In pharmacology, however, it is often a disappointment.*" **MDHOET** supplies the other rule — the one that explains why a free hydroxyl anywhere exposed is usually fatal to activity: "*Most compounds with bare, exposed polar groups like hydroxyls are not centrally active, as they simply do not have any way of getting into the brain.*" What survives at very high doses is interesting precisely because it is not entactogenic: altered colour and depth perception with **no euphoria**, resembling "*a mild dose of ketamine*" — and MDHOET is, per the entry, "*among the most effective of all the N-substituted MDA derivatives assayed in several animal analgesia models*". An analgesic signature, not an empathogenic one. **MDCPM** is the honest null in the set, and Shulgin labels it as such: "*The record of the tasting assay of this compound is pretty embarrassing.*" Ten milligrams is nowhere near a verdict, and because other cyclopropylmethyl compounds (CPM, 2C-T-8) are active, he flags it for reinvestigation rather than filing it as inactive. The distinction between *tested and inactive* and *barely tested* runs throughout Inactive Compounds and the Publishing of Negative Results. **MDMP** is the only one in the table presented as a forward prospect, and the reasoning is clinical rather than recreational: a non-psychedelic, non-serotonin-releasing MDMA-shaped molecule is exactly what a therapist would want if the serotonergic load is the part they are trying to avoid. "*There will have to be a much broader study of its qualitative action in man.*" The naming note attached is a small lesson in collision avoidance: "*MDM should not be used as it has found some currency as an abbreviation for MDMA... MDMP fits neatly with Methylene-Dioxy-Me-Phentermine.*" **MDPL** is the family's oddity: an entry about a compound that contains no pharmacology whatsoever, only a long and genuinely funny argument about whether the three-carbon radical with a triple bond should be called propargyl or propynyl ("*Wait. I'm not done yet!*"). The code is a compromise between the two: "*MDPL takes the first and last letter of the two of them, both propargyl and propynyl.*" ## What the ladder actually teaches Three findings survive the whole family. 1. **Extending the alpha chain costs about a third of the potency per carbon and erodes the social quality first.** METHYL-J keeps MDMA's chronology and loses some of its warmth; by METHYL-K there is nothing left to lose. 1. **Substituting the nitrogen is cheap and almost always destructive.** Benzyl kills it by breaking the two-carbon rule, hydroxyethyl kills it by exposing a polar group, propargyl and cyclopropylmethyl produce nothing at the doses tried. The surviving variations — N-methyl, N-ethyl, N-hydroxy — are small ones. 1. **The series ends in a stack of characterised, untasted solids.** K, L, METHYL-L, ETHYL-L: melting points recorded, human data zero. METHYL-MMDA-2's entry closes with the line that explains why Shulgin published all of it anyway, dead ends included: "*There is a surprisingly large number of inconspicuous chemical explorers out there all over the world, doing their synthetic thing in their private laboratories. They are truly the astronauts of inner space.*" The ladder is published so that the next person climbing it knows which rungs are missing — and knows that the top ones were sawn off deliberately, at 200 milligrams, because "*that is a lot of chemical for the body to have to handle*". ## See also - Naming the Compounds Codes Greek Names and Shulgin Nomenclature — the lettering system and its neighbours - Idiosyncratic Responders Inter-Individual Variance and the Street Market — why METHYL-J's tight dose range is unusual - David E Nichols Entactogen Pharmacology and Receptor Mapping — the entactogen category these compounds define - Chain Length the Bushy End and the Duration of Action — the alpha-chain rule in the wider corpus - Inactive Compounds and the Publishing of Negative Results · Shulgins Open Problems Compounds Left at the Aldehyde and Nitrostyrene Stage - The Shulgin Method Dose Escalation and the Research Group — physical prodrome and sub-threshold escalation - Therapeutic Use as Shulgin Reports It — the clinical-substitute argument behind MDMP - Shulgin Synthetic Method Nitrostyrenes Scrudge and the Reduction Problem — the reductive aminations that built this family - PIHKAL and TIHKAL · Psychedelic and Psychopharmacology Glossary · Shulgin Rating Scale