diff --git a/packages/ketcher-core/src/application/render/renderers/BondRenderer.ts b/packages/ketcher-core/src/application/render/renderers/BondRenderer.ts
index 81062fc21c..4dc73fae56 100644
--- a/packages/ketcher-core/src/application/render/renderers/BondRenderer.ts
+++ b/packages/ketcher-core/src/application/render/renderers/BondRenderer.ts
@@ -198,7 +198,7 @@ export class BondRenderer extends BaseRenderer {
 
   private appendRootElement() {
     return this.canvas
-      .append('g')
+      .insert('g', ':first-child')
       .data([this])
       .attr(
         'transform',
diff --git a/packages/ketcher-core/src/domain/entities/Phosphate.ts b/packages/ketcher-core/src/domain/entities/Phosphate.ts
index 35c7841faf..6935d17ca2 100644
--- a/packages/ketcher-core/src/domain/entities/Phosphate.ts
+++ b/packages/ketcher-core/src/domain/entities/Phosphate.ts
@@ -12,6 +12,10 @@ export class Phosphate extends BaseMonomer {
   }
 
   public getValidSourcePoint(secondMonomer: BaseMonomer) {
+    if (!secondMonomer) {
+      return this.firstFreeAttachmentPoint;
+    }
+
     return this.getValidPoint(
       secondMonomer,
       secondMonomer.potentialSecondAttachmentPointForBond,
@@ -19,6 +23,10 @@ export class Phosphate extends BaseMonomer {
   }
 
   public getValidTargetPoint(firstMonomer: BaseMonomer) {
+    if (!firstMonomer) {
+      return this.firstFreeAttachmentPoint;
+    }
+
     // same implementation for both source and target attachment points
     return this.getValidPoint(
       firstMonomer,
diff --git a/packages/ketcher-core/src/domain/entities/Sugar.ts b/packages/ketcher-core/src/domain/entities/Sugar.ts
index 32b0fd5fd5..87fe401916 100644
--- a/packages/ketcher-core/src/domain/entities/Sugar.ts
+++ b/packages/ketcher-core/src/domain/entities/Sugar.ts
@@ -9,7 +9,11 @@ import { isRnaBaseOrAmbiguousRnaBase } from 'domain/helpers/monomers';
 import { IVariantMonomer } from 'domain/entities/types';
 
 export class Sugar extends BaseMonomer {
-  public getValidSourcePoint(secondMonomer: BaseMonomer & IVariantMonomer) {
+  public getValidSourcePoint(secondMonomer?: BaseMonomer & IVariantMonomer) {
+    if (!secondMonomer) {
+      return this.firstFreeAttachmentPoint;
+    }
+
     return this.getValidPoint(
       secondMonomer,
       secondMonomer.potentialSecondAttachmentPointForBond,
@@ -17,6 +21,10 @@ export class Sugar extends BaseMonomer {
   }
 
   public getValidTargetPoint(firstMonomer: BaseMonomer & IVariantMonomer) {
+    if (!firstMonomer) {
+      return this.firstFreeAttachmentPoint;
+    }
+
     // same implementation for both source and target attachment points
     return this.getValidPoint(
       firstMonomer,
diff --git a/packages/ketcher-core/src/domain/entities/UnresolvedMonomer.ts b/packages/ketcher-core/src/domain/entities/UnresolvedMonomer.ts
index c3314fc02f..f5df3fd2d3 100644
--- a/packages/ketcher-core/src/domain/entities/UnresolvedMonomer.ts
+++ b/packages/ketcher-core/src/domain/entities/UnresolvedMonomer.ts
@@ -5,12 +5,20 @@ import { SubChainNode } from 'domain/entities/monomer-chains/types';
 import { Peptide } from 'domain/entities/Peptide';
 
 export class UnresolvedMonomer extends BaseMonomer {
-  public getValidSourcePoint(monomer?: BaseMonomer) {
-    return Peptide.prototype.getValidSourcePoint.call(this, monomer);
+  public getValidSourcePoint(secondMonomer?: BaseMonomer) {
+    if (!secondMonomer) {
+      return this.firstFreeAttachmentPoint;
+    }
+
+    return Peptide.prototype.getValidSourcePoint.call(this, secondMonomer);
   }
 
-  public getValidTargetPoint(monomer: BaseMonomer) {
-    return Peptide.prototype.getValidTargetPoint.call(this, monomer);
+  public getValidTargetPoint(firstMonomer: BaseMonomer) {
+    if (!firstMonomer) {
+      return this.firstFreeAttachmentPoint;
+    }
+
+    return Peptide.prototype.getValidTargetPoint.call(this, firstMonomer);
   }
 
   public get SubChainConstructor() {