gbranden pushed a commit to branch master
in repository groff.
commit e341e0090c7d4fe0196170006d29705b18e9c1a2
Author: Norwid Behrnd <[email protected]>
AuthorDate: Wed Dec 31 22:29:01 2025 +0100
[chem]: Add stereochemistry to cholesterol.
* contrib/chem/examples/cholesterol.chem: Add stereochemistry.
- The previous depiction was incomplete and did not explicitly
described the stereogenic centres as such. This information was
added with `front bond` and `back bond` as available with groff
1.23.0. If possible, future versions should use a wedge shaped
version of `back bond`.
- Particular about steroids: among chemists, it is more common to name
the four rings by A, B, C, and D. To use these labels instead of
R1, R2, etc. equally displays chem's flexibility here.
- The orientation of cycles allowed simplifying the definition of
their mutual attachment.
Fixes <https://savannah.gnu.org/bugs/?67873>.
Signed-off-by: Norwid Behrnd <[email protected]>
---
contrib/chem/ChangeLog | 17 +++++++++++++++++
contrib/chem/examples/cholesterol.chem | 33 ++++++++++++++++++++-------------
2 files changed, 37 insertions(+), 13 deletions(-)
diff --git a/contrib/chem/ChangeLog b/contrib/chem/ChangeLog
index a83f85c06..ff76cc5ee 100644
--- a/contrib/chem/ChangeLog
+++ b/contrib/chem/ChangeLog
@@ -1,3 +1,20 @@
+2025-12-31 Norwid Behrnd <[email protected]>
+
+ * examples/cholesterol.chem: Add stereochemistry.
+ - The previous depiction was incomplete and did not explicitly
+ described the stereogenic centres as such. This information
+ was added with `front bond` and `back bond` as available with
+ groff 1.23.0. If possible, future versions should use a wedge
+ shaped version of `back bond`.
+ - Particular about steroids: among chemists, it is more common
+ to name the four rings by A, B, C, and D. To use these labels
+ instead of R1, R2, etc. equally displays chem's flexibility
+ here.
+ - The orientation of cycles allowed simplifying the definition
+ of their mutual attachment.
+
+ Fixes <https://savannah.gnu.org/bugs/?67873>.
+
2025-12-31 Norwid Behrnd <[email protected]>
* examples/cholesterin.chem: Rename this...
diff --git a/contrib/chem/examples/cholesterol.chem
b/contrib/chem/examples/cholesterol.chem
index 564416ce0..2f9091bf5 100644
--- a/contrib/chem/examples/cholesterol.chem
+++ b/contrib/chem/examples/cholesterol.chem
@@ -1,20 +1,27 @@
-cholesterin.chem:
+cholesterol.chem:
.cstart
# Example file for chem:
-# Cholesterin or C27_H46O or
-# 10,13-dimethyl-17-(6-methylheptan-2-yl)-2,3,4,5,6,9,11,12,14,15,16,17-
-# dodecahydro-1H-cyclopenta[a]phenanthren-3-ol
+# cholesterol or C27_H46_O or
+# cholest-5-en-3β-ol (CAS-RN 57-88-5)
-R1: ring6
- bond -120 ; HO
-R2: ring6 with .V5 at R1.V3 with .V6 at R1.V2 double 4,5
- bond up at R2.V6
-R3: ring6 with .V5 at R2.V1 with .V4 at R2.V2
-R4: flatring5 pointing up with .V4 at R3.V3 with .V5 at R3.V2
- bond up at R4.V5
- bond up at R4.V1
-B1: bond -60
+# Ring names as in rule 3S-1.1 of IUPAC recommendations 1989 (see for
+# instance https://iupac.qmul.ac.uk/steroid/3S01.html)
+
+A: ring6
+B: ring6 with .V5 at A.V3 double 4,5
+C: ring6 with .V5 at B.V1
+D: ring5 pointing right with .V4 at C.V2
+
+ front bond up at A.V2
+ front bond -120 at A.V5 ; HO
+ back bond down at B.V1 ; H
+ front bond up at B.V2 ; H
+ front bond up at C.V2
+ back bond down at C.V3 ; H
+ back bond 60 at D.V5 ; H
+ bond up at D.V5
+B1: back bond -60
bond 60 at B1.start
bond 120
bond 60
_______________________________________________
groff-commit mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/groff-commit
